1//===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//===----------------------------------------------------------------------===//
7//
8// This file implements semantic analysis for C++ templates.
9//===----------------------------------------------------------------------===//
10
11#include "TreeTransform.h"
12#include "clang/AST/ASTConsumer.h"
13#include "clang/AST/ASTContext.h"
14#include "clang/AST/DeclFriend.h"
15#include "clang/AST/DeclTemplate.h"
16#include "clang/AST/Expr.h"
17#include "clang/AST/ExprCXX.h"
18#include "clang/AST/RecursiveASTVisitor.h"
19#include "clang/AST/TypeVisitor.h"
20#include "clang/Basic/Builtins.h"
21#include "clang/Basic/LangOptions.h"
22#include "clang/Basic/PartialDiagnostic.h"
23#include "clang/Basic/Stack.h"
24#include "clang/Basic/TargetInfo.h"
25#include "clang/Sema/DeclSpec.h"
26#include "clang/Sema/Initialization.h"
27#include "clang/Sema/Lookup.h"
28#include "clang/Sema/Overload.h"
29#include "clang/Sema/ParsedTemplate.h"
30#include "clang/Sema/Scope.h"
31#include "clang/Sema/SemaInternal.h"
32#include "clang/Sema/Template.h"
33#include "clang/Sema/TemplateDeduction.h"
34#include "llvm/ADT/SmallBitVector.h"
35#include "llvm/ADT/SmallString.h"
36#include "llvm/ADT/StringExtras.h"
37
38#include <iterator>
39using namespace clang;
40using namespace sema;
41
42// Exported for use by Parser.
43SourceRange
44clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
45 unsigned N) {
46 if (!N) return SourceRange();
47 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
48}
49
50unsigned Sema::getTemplateDepth(Scope *S) const {
51 unsigned Depth = 0;
52
53 // Each template parameter scope represents one level of template parameter
54 // depth.
55 for (Scope *TempParamScope = S->getTemplateParamParent(); TempParamScope;
56 TempParamScope = TempParamScope->getParent()->getTemplateParamParent()) {
57 ++Depth;
58 }
59
60 // Note that there are template parameters with the given depth.
61 auto ParamsAtDepth = [&](unsigned D) { Depth = std::max(Depth, D + 1); };
62
63 // Look for parameters of an enclosing generic lambda. We don't create a
64 // template parameter scope for these.
65 for (FunctionScopeInfo *FSI : getFunctionScopes()) {
66 if (auto *LSI = dyn_cast<LambdaScopeInfo>(FSI)) {
67 if (!LSI->TemplateParams.empty()) {
68 ParamsAtDepth(LSI->AutoTemplateParameterDepth);
69 break;
70 }
71 if (LSI->GLTemplateParameterList) {
72 ParamsAtDepth(LSI->GLTemplateParameterList->getDepth());
73 break;
74 }
75 }
76 }
77
78 // Look for parameters of an enclosing terse function template. We don't
79 // create a template parameter scope for these either.
80 for (const InventedTemplateParameterInfo &Info :
81 getInventedParameterInfos()) {
82 if (!Info.TemplateParams.empty()) {
83 ParamsAtDepth(Info.AutoTemplateParameterDepth);
84 break;
85 }
86 }
87
88 return Depth;
89}
90
91/// \brief Determine whether the declaration found is acceptable as the name
92/// of a template and, if so, return that template declaration. Otherwise,
93/// returns null.
94///
95/// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
96/// is true. In all other cases it will return a TemplateDecl (or null).
97NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
98 bool AllowFunctionTemplates,
99 bool AllowDependent) {
100 D = D->getUnderlyingDecl();
101
102 if (isa<TemplateDecl>(D)) {
103 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
104 return nullptr;
105
106 return D;
107 }
108
109 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
110 // C++ [temp.local]p1:
111 // Like normal (non-template) classes, class templates have an
112 // injected-class-name (Clause 9). The injected-class-name
113 // can be used with or without a template-argument-list. When
114 // it is used without a template-argument-list, it is
115 // equivalent to the injected-class-name followed by the
116 // template-parameters of the class template enclosed in
117 // <>. When it is used with a template-argument-list, it
118 // refers to the specified class template specialization,
119 // which could be the current specialization or another
120 // specialization.
121 if (Record->isInjectedClassName()) {
122 Record = cast<CXXRecordDecl>(Record->getDeclContext());
123 if (Record->getDescribedClassTemplate())
124 return Record->getDescribedClassTemplate();
125
126 if (ClassTemplateSpecializationDecl *Spec
127 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
128 return Spec->getSpecializedTemplate();
129 }
130
131 return nullptr;
132 }
133
134 // 'using Dependent::foo;' can resolve to a template name.
135 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
136 // injected-class-name).
137 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
138 return D;
139
140 return nullptr;
141}
142
143void Sema::FilterAcceptableTemplateNames(LookupResult &R,
144 bool AllowFunctionTemplates,
145 bool AllowDependent) {
146 LookupResult::Filter filter = R.makeFilter();
147 while (filter.hasNext()) {
148 NamedDecl *Orig = filter.next();
149 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
150 filter.erase();
151 }
152 filter.done();
153}
154
155bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
156 bool AllowFunctionTemplates,
157 bool AllowDependent,
158 bool AllowNonTemplateFunctions) {
159 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
160 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
161 return true;
162 if (AllowNonTemplateFunctions &&
163 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
164 return true;
165 }
166
167 return false;
168}
169
170TemplateNameKind Sema::isTemplateName(Scope *S,
171 CXXScopeSpec &SS,
172 bool hasTemplateKeyword,
173 const UnqualifiedId &Name,
174 ParsedType ObjectTypePtr,
175 bool EnteringContext,
176 TemplateTy &TemplateResult,
177 bool &MemberOfUnknownSpecialization,
178 bool Disambiguation) {
179 assert(getLangOpts().CPlusPlus && "No template names in C!");
180
181 DeclarationName TName;
182 MemberOfUnknownSpecialization = false;
183
184 switch (Name.getKind()) {
185 case UnqualifiedIdKind::IK_Identifier:
186 TName = DeclarationName(Name.Identifier);
187 break;
188
189 case UnqualifiedIdKind::IK_OperatorFunctionId:
190 TName = Context.DeclarationNames.getCXXOperatorName(
191 Name.OperatorFunctionId.Operator);
192 break;
193
194 case UnqualifiedIdKind::IK_LiteralOperatorId:
195 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
196 break;
197
198 default:
199 return TNK_Non_template;
200 }
201
202 QualType ObjectType = ObjectTypePtr.get();
203
204 AssumedTemplateKind AssumedTemplate;
205 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
206 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
207 MemberOfUnknownSpecialization, SourceLocation(),
208 &AssumedTemplate,
209 /*AllowTypoCorrection=*/!Disambiguation))
210 return TNK_Non_template;
211
212 if (AssumedTemplate != AssumedTemplateKind::None) {
213 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
214 // Let the parser know whether we found nothing or found functions; if we
215 // found nothing, we want to more carefully check whether this is actually
216 // a function template name versus some other kind of undeclared identifier.
217 return AssumedTemplate == AssumedTemplateKind::FoundNothing
218 ? TNK_Undeclared_template
219 : TNK_Function_template;
220 }
221
222 if (R.empty())
223 return TNK_Non_template;
224
225 NamedDecl *D = nullptr;
226 if (R.isAmbiguous()) {
227 // If we got an ambiguity involving a non-function template, treat this
228 // as a template name, and pick an arbitrary template for error recovery.
229 bool AnyFunctionTemplates = false;
230 for (NamedDecl *FoundD : R) {
231 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
232 if (isa<FunctionTemplateDecl>(FoundTemplate))
233 AnyFunctionTemplates = true;
234 else {
235 D = FoundTemplate;
236 break;
237 }
238 }
239 }
240
241 // If we didn't find any templates at all, this isn't a template name.
242 // Leave the ambiguity for a later lookup to diagnose.
243 if (!D && !AnyFunctionTemplates) {
244 R.suppressDiagnostics();
245 return TNK_Non_template;
246 }
247
248 // If the only templates were function templates, filter out the rest.
249 // We'll diagnose the ambiguity later.
250 if (!D)
251 FilterAcceptableTemplateNames(R);
252 }
253
254 // At this point, we have either picked a single template name declaration D
255 // or we have a non-empty set of results R containing either one template name
256 // declaration or a set of function templates.
257
258 TemplateName Template;
259 TemplateNameKind TemplateKind;
260
261 unsigned ResultCount = R.end() - R.begin();
262 if (!D && ResultCount > 1) {
263 // We assume that we'll preserve the qualifier from a function
264 // template name in other ways.
265 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
266 TemplateKind = TNK_Function_template;
267
268 // We'll do this lookup again later.
269 R.suppressDiagnostics();
270 } else {
271 if (!D) {
272 D = getAsTemplateNameDecl(*R.begin());
273 assert(D && "unambiguous result is not a template name");
274 }
275
276 if (isa<UnresolvedUsingValueDecl>(D)) {
277 // We don't yet know whether this is a template-name or not.
278 MemberOfUnknownSpecialization = true;
279 return TNK_Non_template;
280 }
281
282 TemplateDecl *TD = cast<TemplateDecl>(D);
283
284 if (SS.isSet() && !SS.isInvalid()) {
285 NestedNameSpecifier *Qualifier = SS.getScopeRep();
286 Template = Context.getQualifiedTemplateName(Qualifier,
287 hasTemplateKeyword, TD);
288 } else {
289 Template = TemplateName(TD);
290 }
291
292 if (isa<FunctionTemplateDecl>(TD)) {
293 TemplateKind = TNK_Function_template;
294
295 // We'll do this lookup again later.
296 R.suppressDiagnostics();
297 } else {
298 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
299 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
300 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
301 TemplateKind =
302 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
303 isa<ConceptDecl>(TD) ? TNK_Concept_template :
304 TNK_Type_template;
305 }
306 }
307
308 TemplateResult = TemplateTy::make(Template);
309 return TemplateKind;
310}
311
312bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
313 SourceLocation NameLoc,
314 ParsedTemplateTy *Template) {
315 CXXScopeSpec SS;
316 bool MemberOfUnknownSpecialization = false;
317
318 // We could use redeclaration lookup here, but we don't need to: the
319 // syntactic form of a deduction guide is enough to identify it even
320 // if we can't look up the template name at all.
321 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
322 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
323 /*EnteringContext*/ false,
324 MemberOfUnknownSpecialization))
325 return false;
326
327 if (R.empty()) return false;
328 if (R.isAmbiguous()) {
329 // FIXME: Diagnose an ambiguity if we find at least one template.
330 R.suppressDiagnostics();
331 return false;
332 }
333
334 // We only treat template-names that name type templates as valid deduction
335 // guide names.
336 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
337 if (!TD || !getAsTypeTemplateDecl(TD))
338 return false;
339
340 if (Template)
341 *Template = TemplateTy::make(TemplateName(TD));
342 return true;
343}
344
345bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
346 SourceLocation IILoc,
347 Scope *S,
348 const CXXScopeSpec *SS,
349 TemplateTy &SuggestedTemplate,
350 TemplateNameKind &SuggestedKind) {
351 // We can't recover unless there's a dependent scope specifier preceding the
352 // template name.
353 // FIXME: Typo correction?
354 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
355 computeDeclContext(*SS))
356 return false;
357
358 // The code is missing a 'template' keyword prior to the dependent template
359 // name.
360 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
361 Diag(IILoc, diag::err_template_kw_missing)
362 << Qualifier << II.getName()
363 << FixItHint::CreateInsertion(IILoc, "template ");
364 SuggestedTemplate
365 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
366 SuggestedKind = TNK_Dependent_template_name;
367 return true;
368}
369
370bool Sema::LookupTemplateName(LookupResult &Found,
371 Scope *S, CXXScopeSpec &SS,
372 QualType ObjectType,
373 bool EnteringContext,
374 bool &MemberOfUnknownSpecialization,
375 RequiredTemplateKind RequiredTemplate,
376 AssumedTemplateKind *ATK,
377 bool AllowTypoCorrection) {
378 if (ATK)
379 *ATK = AssumedTemplateKind::None;
380
381 if (SS.isInvalid())
382 return true;
383
384 Found.setTemplateNameLookup(true);
385
386 // Determine where to perform name lookup
387 MemberOfUnknownSpecialization = false;
388 DeclContext *LookupCtx = nullptr;
389 bool IsDependent = false;
390 if (!ObjectType.isNull()) {
391 // This nested-name-specifier occurs in a member access expression, e.g.,
392 // x->B::f, and we are looking into the type of the object.
393 assert(SS.isEmpty() && "ObjectType and scope specifier cannot coexist");
394 LookupCtx = computeDeclContext(ObjectType);
395 IsDependent = !LookupCtx && ObjectType->isDependentType();
396 assert((IsDependent || !ObjectType->isIncompleteType() ||
397 ObjectType->castAs<TagType>()->isBeingDefined()) &&
398 "Caller should have completed object type");
399
400 // Template names cannot appear inside an Objective-C class or object type
401 // or a vector type.
402 //
403 // FIXME: This is wrong. For example:
404 //
405 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
406 // Vec<int> vi;
407 // vi.Vec<int>::~Vec<int>();
408 //
409 // ... should be accepted but we will not treat 'Vec' as a template name
410 // here. The right thing to do would be to check if the name is a valid
411 // vector component name, and look up a template name if not. And similarly
412 // for lookups into Objective-C class and object types, where the same
413 // problem can arise.
414 if (ObjectType->isObjCObjectOrInterfaceType() ||
415 ObjectType->isVectorType()) {
416 Found.clear();
417 return false;
418 }
419 } else if (SS.isNotEmpty()) {
420 // This nested-name-specifier occurs after another nested-name-specifier,
421 // so long into the context associated with the prior nested-name-specifier.
422 LookupCtx = computeDeclContext(SS, EnteringContext);
423 IsDependent = !LookupCtx && isDependentScopeSpecifier(SS);
424
425 // The declaration context must be complete.
426 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
427 return true;
428 }
429
430 bool ObjectTypeSearchedInScope = false;
431 bool AllowFunctionTemplatesInLookup = true;
432 if (LookupCtx) {
433 // Perform "qualified" name lookup into the declaration context we
434 // computed, which is either the type of the base of a member access
435 // expression or the declaration context associated with a prior
436 // nested-name-specifier.
437 LookupQualifiedName(Found, LookupCtx);
438
439 // FIXME: The C++ standard does not clearly specify what happens in the
440 // case where the object type is dependent, and implementations vary. In
441 // Clang, we treat a name after a . or -> as a template-name if lookup
442 // finds a non-dependent member or member of the current instantiation that
443 // is a type template, or finds no such members and lookup in the context
444 // of the postfix-expression finds a type template. In the latter case, the
445 // name is nonetheless dependent, and we may resolve it to a member of an
446 // unknown specialization when we come to instantiate the template.
447 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
448 }
449
450 if (SS.isEmpty() && (ObjectType.isNull() || Found.empty())) {
451 // C++ [basic.lookup.classref]p1:
452 // In a class member access expression (5.2.5), if the . or -> token is
453 // immediately followed by an identifier followed by a <, the
454 // identifier must be looked up to determine whether the < is the
455 // beginning of a template argument list (14.2) or a less-than operator.
456 // The identifier is first looked up in the class of the object
457 // expression. If the identifier is not found, it is then looked up in
458 // the context of the entire postfix-expression and shall name a class
459 // template.
460 if (S)
461 LookupName(Found, S);
462
463 if (!ObjectType.isNull()) {
464 // FIXME: We should filter out all non-type templates here, particularly
465 // variable templates and concepts. But the exclusion of alias templates
466 // and template template parameters is a wording defect.
467 AllowFunctionTemplatesInLookup = false;
468 ObjectTypeSearchedInScope = true;
469 }
470
471 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
472 }
473
474 if (Found.isAmbiguous())
475 return false;
476
477 if (ATK && SS.isEmpty() && ObjectType.isNull() &&
478 !RequiredTemplate.hasTemplateKeyword()) {
479 // C++2a [temp.names]p2:
480 // A name is also considered to refer to a template if it is an
481 // unqualified-id followed by a < and name lookup finds either one or more
482 // functions or finds nothing.
483 //
484 // To keep our behavior consistent, we apply the "finds nothing" part in
485 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
486 // successfully form a call to an undeclared template-id.
487 bool AllFunctions =
488 getLangOpts().CPlusPlus20 &&
489 std::all_of(Found.begin(), Found.end(), [](NamedDecl *ND) {
490 return isa<FunctionDecl>(ND->getUnderlyingDecl());
491 });
492 if (AllFunctions || (Found.empty() && !IsDependent)) {
493 // If lookup found any functions, or if this is a name that can only be
494 // used for a function, then strongly assume this is a function
495 // template-id.
496 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
497 ? AssumedTemplateKind::FoundNothing
498 : AssumedTemplateKind::FoundFunctions;
499 Found.clear();
500 return false;
501 }
502 }
503
504 if (Found.empty() && !IsDependent && AllowTypoCorrection) {
505 // If we did not find any names, and this is not a disambiguation, attempt
506 // to correct any typos.
507 DeclarationName Name = Found.getLookupName();
508 Found.clear();
509 // Simple filter callback that, for keywords, only accepts the C++ *_cast
510 DefaultFilterCCC FilterCCC{};
511 FilterCCC.WantTypeSpecifiers = false;
512 FilterCCC.WantExpressionKeywords = false;
513 FilterCCC.WantRemainingKeywords = false;
514 FilterCCC.WantCXXNamedCasts = true;
515 if (TypoCorrection Corrected =
516 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
517 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
518 if (auto *ND = Corrected.getFoundDecl())
519 Found.addDecl(ND);
520 FilterAcceptableTemplateNames(Found);
521 if (Found.isAmbiguous()) {
522 Found.clear();
523 } else if (!Found.empty()) {
524 Found.setLookupName(Corrected.getCorrection());
525 if (LookupCtx) {
526 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
527 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
528 Name.getAsString() == CorrectedStr;
529 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
530 << Name << LookupCtx << DroppedSpecifier
531 << SS.getRange());
532 } else {
533 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
534 }
535 }
536 }
537 }
538
539 NamedDecl *ExampleLookupResult =
540 Found.empty() ? nullptr : Found.getRepresentativeDecl();
541 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
542 if (Found.empty()) {
543 if (IsDependent) {
544 MemberOfUnknownSpecialization = true;
545 return false;
546 }
547
548 // If a 'template' keyword was used, a lookup that finds only non-template
549 // names is an error.
550 if (ExampleLookupResult && RequiredTemplate) {
551 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
552 << Found.getLookupName() << SS.getRange()
553 << RequiredTemplate.hasTemplateKeyword()
554 << RequiredTemplate.getTemplateKeywordLoc();
555 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
556 diag::note_template_kw_refers_to_non_template)
557 << Found.getLookupName();
558 return true;
559 }
560
561 return false;
562 }
563
564 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
565 !getLangOpts().CPlusPlus11) {
566 // C++03 [basic.lookup.classref]p1:
567 // [...] If the lookup in the class of the object expression finds a
568 // template, the name is also looked up in the context of the entire
569 // postfix-expression and [...]
570 //
571 // Note: C++11 does not perform this second lookup.
572 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
573 LookupOrdinaryName);
574 FoundOuter.setTemplateNameLookup(true);
575 LookupName(FoundOuter, S);
576 // FIXME: We silently accept an ambiguous lookup here, in violation of
577 // [basic.lookup]/1.
578 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
579
580 NamedDecl *OuterTemplate;
581 if (FoundOuter.empty()) {
582 // - if the name is not found, the name found in the class of the
583 // object expression is used, otherwise
584 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
585 !(OuterTemplate =
586 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
587 // - if the name is found in the context of the entire
588 // postfix-expression and does not name a class template, the name
589 // found in the class of the object expression is used, otherwise
590 FoundOuter.clear();
591 } else if (!Found.isSuppressingDiagnostics()) {
592 // - if the name found is a class template, it must refer to the same
593 // entity as the one found in the class of the object expression,
594 // otherwise the program is ill-formed.
595 if (!Found.isSingleResult() ||
596 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
597 OuterTemplate->getCanonicalDecl()) {
598 Diag(Found.getNameLoc(),
599 diag::ext_nested_name_member_ref_lookup_ambiguous)
600 << Found.getLookupName()
601 << ObjectType;
602 Diag(Found.getRepresentativeDecl()->getLocation(),
603 diag::note_ambig_member_ref_object_type)
604 << ObjectType;
605 Diag(FoundOuter.getFoundDecl()->getLocation(),
606 diag::note_ambig_member_ref_scope);
607
608 // Recover by taking the template that we found in the object
609 // expression's type.
610 }
611 }
612 }
613
614 return false;
615}
616
617void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
618 SourceLocation Less,
619 SourceLocation Greater) {
620 if (TemplateName.isInvalid())
621 return;
622
623 DeclarationNameInfo NameInfo;
624 CXXScopeSpec SS;
625 LookupNameKind LookupKind;
626
627 DeclContext *LookupCtx = nullptr;
628 NamedDecl *Found = nullptr;
629 bool MissingTemplateKeyword = false;
630
631 // Figure out what name we looked up.
632 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
633 NameInfo = DRE->getNameInfo();
634 SS.Adopt(DRE->getQualifierLoc());
635 LookupKind = LookupOrdinaryName;
636 Found = DRE->getFoundDecl();
637 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
638 NameInfo = ME->getMemberNameInfo();
639 SS.Adopt(ME->getQualifierLoc());
640 LookupKind = LookupMemberName;
641 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
642 Found = ME->getMemberDecl();
643 } else if (auto *DSDRE =
644 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
645 NameInfo = DSDRE->getNameInfo();
646 SS.Adopt(DSDRE->getQualifierLoc());
647 MissingTemplateKeyword = true;
648 } else if (auto *DSME =
649 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
650 NameInfo = DSME->getMemberNameInfo();
651 SS.Adopt(DSME->getQualifierLoc());
652 MissingTemplateKeyword = true;
653 } else {
654 llvm_unreachable("unexpected kind of potential template name");
655 }
656
657 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
658 // was missing.
659 if (MissingTemplateKeyword) {
660 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
661 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
662 return;
663 }
664
665 // Try to correct the name by looking for templates and C++ named casts.
666 struct TemplateCandidateFilter : CorrectionCandidateCallback {
667 Sema &S;
668 TemplateCandidateFilter(Sema &S) : S(S) {
669 WantTypeSpecifiers = false;
670 WantExpressionKeywords = false;
671 WantRemainingKeywords = false;
672 WantCXXNamedCasts = true;
673 };
674 bool ValidateCandidate(const TypoCorrection &Candidate) override {
675 if (auto *ND = Candidate.getCorrectionDecl())
676 return S.getAsTemplateNameDecl(ND);
677 return Candidate.isKeyword();
678 }
679
680 std::unique_ptr<CorrectionCandidateCallback> clone() override {
681 return std::make_unique<TemplateCandidateFilter>(*this);
682 }
683 };
684
685 DeclarationName Name = NameInfo.getName();
686 TemplateCandidateFilter CCC(*this);
687 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
688 CTK_ErrorRecovery, LookupCtx)) {
689 auto *ND = Corrected.getFoundDecl();
690 if (ND)
691 ND = getAsTemplateNameDecl(ND);
692 if (ND || Corrected.isKeyword()) {
693 if (LookupCtx) {
694 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
695 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
696 Name.getAsString() == CorrectedStr;
697 diagnoseTypo(Corrected,
698 PDiag(diag::err_non_template_in_member_template_id_suggest)
699 << Name << LookupCtx << DroppedSpecifier
700 << SS.getRange(), false);
701 } else {
702 diagnoseTypo(Corrected,
703 PDiag(diag::err_non_template_in_template_id_suggest)
704 << Name, false);
705 }
706 if (Found)
707 Diag(Found->getLocation(),
708 diag::note_non_template_in_template_id_found);
709 return;
710 }
711 }
712
713 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
714 << Name << SourceRange(Less, Greater);
715 if (Found)
716 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
717}
718
719/// ActOnDependentIdExpression - Handle a dependent id-expression that
720/// was just parsed. This is only possible with an explicit scope
721/// specifier naming a dependent type.
722ExprResult
723Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
724 SourceLocation TemplateKWLoc,
725 const DeclarationNameInfo &NameInfo,
726 bool isAddressOfOperand,
727 const TemplateArgumentListInfo *TemplateArgs) {
728 DeclContext *DC = getFunctionLevelDeclContext();
729
730 // C++11 [expr.prim.general]p12:
731 // An id-expression that denotes a non-static data member or non-static
732 // member function of a class can only be used:
733 // (...)
734 // - if that id-expression denotes a non-static data member and it
735 // appears in an unevaluated operand.
736 //
737 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
738 // CXXDependentScopeMemberExpr. The former can instantiate to either
739 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
740 // always a MemberExpr.
741 bool MightBeCxx11UnevalField =
742 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
743
744 // Check if the nested name specifier is an enum type.
745 bool IsEnum = false;
746 if (NestedNameSpecifier *NNS = SS.getScopeRep())
747 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
748
749 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
750 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
751 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
752
753 // Since the 'this' expression is synthesized, we don't need to
754 // perform the double-lookup check.
755 NamedDecl *FirstQualifierInScope = nullptr;
756
757 return CXXDependentScopeMemberExpr::Create(
758 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
759 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
760 FirstQualifierInScope, NameInfo, TemplateArgs);
761 }
762
763 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
764}
765
766ExprResult
767Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
768 SourceLocation TemplateKWLoc,
769 const DeclarationNameInfo &NameInfo,
770 const TemplateArgumentListInfo *TemplateArgs) {
771 // DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
772 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
773 if (!QualifierLoc)
774 return ExprError();
775
776 return DependentScopeDeclRefExpr::Create(
777 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
778}
779
780
781/// Determine whether we would be unable to instantiate this template (because
782/// it either has no definition, or is in the process of being instantiated).
783bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
784 NamedDecl *Instantiation,
785 bool InstantiatedFromMember,
786 const NamedDecl *Pattern,
787 const NamedDecl *PatternDef,
788 TemplateSpecializationKind TSK,
789 bool Complain /*= true*/) {
790 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
791 isa<VarDecl>(Instantiation));
792
793 bool IsEntityBeingDefined = false;
794 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
795 IsEntityBeingDefined = TD->isBeingDefined();
796
797 if (PatternDef && !IsEntityBeingDefined) {
798 NamedDecl *SuggestedDef = nullptr;
799 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
800 /*OnlyNeedComplete*/false)) {
801 // If we're allowed to diagnose this and recover, do so.
802 bool Recover = Complain && !isSFINAEContext();
803 if (Complain)
804 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
805 Sema::MissingImportKind::Definition, Recover);
806 return !Recover;
807 }
808 return false;
809 }
810
811 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
812 return true;
813
814 llvm::Optional<unsigned> Note;
815 QualType InstantiationTy;
816 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
817 InstantiationTy = Context.getTypeDeclType(TD);
818 if (PatternDef) {
819 Diag(PointOfInstantiation,
820 diag::err_template_instantiate_within_definition)
821 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
822 << InstantiationTy;
823 // Not much point in noting the template declaration here, since
824 // we're lexically inside it.
825 Instantiation->setInvalidDecl();
826 } else if (InstantiatedFromMember) {
827 if (isa<FunctionDecl>(Instantiation)) {
828 Diag(PointOfInstantiation,
829 diag::err_explicit_instantiation_undefined_member)
830 << /*member function*/ 1 << Instantiation->getDeclName()
831 << Instantiation->getDeclContext();
832 Note = diag::note_explicit_instantiation_here;
833 } else {
834 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
835 Diag(PointOfInstantiation,
836 diag::err_implicit_instantiate_member_undefined)
837 << InstantiationTy;
838 Note = diag::note_member_declared_at;
839 }
840 } else {
841 if (isa<FunctionDecl>(Instantiation)) {
842 Diag(PointOfInstantiation,
843 diag::err_explicit_instantiation_undefined_func_template)
844 << Pattern;
845 Note = diag::note_explicit_instantiation_here;
846 } else if (isa<TagDecl>(Instantiation)) {
847 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
848 << (TSK != TSK_ImplicitInstantiation)
849 << InstantiationTy;
850 Note = diag::note_template_decl_here;
851 } else {
852 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
853 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
854 Diag(PointOfInstantiation,
855 diag::err_explicit_instantiation_undefined_var_template)
856 << Instantiation;
857 Instantiation->setInvalidDecl();
858 } else
859 Diag(PointOfInstantiation,
860 diag::err_explicit_instantiation_undefined_member)
861 << /*static data member*/ 2 << Instantiation->getDeclName()
862 << Instantiation->getDeclContext();
863 Note = diag::note_explicit_instantiation_here;
864 }
865 }
866 if (Note) // Diagnostics were emitted.
867 Diag(Pattern->getLocation(), Note.getValue());
868
869 // In general, Instantiation isn't marked invalid to get more than one
870 // error for multiple undefined instantiations. But the code that does
871 // explicit declaration -> explicit definition conversion can't handle
872 // invalid declarations, so mark as invalid in that case.
873 if (TSK == TSK_ExplicitInstantiationDeclaration)
874 Instantiation->setInvalidDecl();
875 return true;
876}
877
878/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
879/// that the template parameter 'PrevDecl' is being shadowed by a new
880/// declaration at location Loc. Returns true to indicate that this is
881/// an error, and false otherwise.
882void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
883 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
884
885 // C++ [temp.local]p4:
886 // A template-parameter shall not be redeclared within its
887 // scope (including nested scopes).
888 //
889 // Make this a warning when MSVC compatibility is requested.
890 unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
891 : diag::err_template_param_shadow;
892 Diag(Loc, DiagId) << cast<NamedDecl>(PrevDecl)->getDeclName();
893 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
894}
895
896/// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
897/// the parameter D to reference the templated declaration and return a pointer
898/// to the template declaration. Otherwise, do nothing to D and return null.
899TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
900 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
901 D = Temp->getTemplatedDecl();
902 return Temp;
903 }
904 return nullptr;
905}
906
907ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
908 SourceLocation EllipsisLoc) const {
909 assert(Kind == Template &&
910 "Only template template arguments can be pack expansions here");
911 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
912 "Template template argument pack expansion without packs");
913 ParsedTemplateArgument Result(*this);
914 Result.EllipsisLoc = EllipsisLoc;
915 return Result;
916}
917
918static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
919 const ParsedTemplateArgument &Arg) {
920
921 switch (Arg.getKind()) {
922 case ParsedTemplateArgument::Type: {
923 TypeSourceInfo *DI;
924 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
925 if (!DI)
926 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
927 return TemplateArgumentLoc(TemplateArgument(T), DI);
928 }
929
930 case ParsedTemplateArgument::NonType: {
931 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
932 return TemplateArgumentLoc(TemplateArgument(E), E);
933 }
934
935 case ParsedTemplateArgument::Template: {
936 TemplateName Template = Arg.getAsTemplate().get();
937 TemplateArgument TArg;
938 if (Arg.getEllipsisLoc().isValid())
939 TArg = TemplateArgument(Template, Optional<unsigned int>());
940 else
941 TArg = Template;
942 return TemplateArgumentLoc(
943 SemaRef.Context, TArg,
944 Arg.getScopeSpec().getWithLocInContext(SemaRef.Context),
945 Arg.getLocation(), Arg.getEllipsisLoc());
946 }
947 }
948
949 llvm_unreachable("Unhandled parsed template argument");
950}
951
952/// Translates template arguments as provided by the parser
953/// into template arguments used by semantic analysis.
954void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
955 TemplateArgumentListInfo &TemplateArgs) {
956 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
957 TemplateArgs.addArgument(translateTemplateArgument(*this,
958 TemplateArgsIn[I]));
959}
960
961static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
962 SourceLocation Loc,
963 IdentifierInfo *Name) {
964 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
965 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
966 if (PrevDecl && PrevDecl->isTemplateParameter())
967 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
968}
969
970/// Convert a parsed type into a parsed template argument. This is mostly
971/// trivial, except that we may have parsed a C++17 deduced class template
972/// specialization type, in which case we should form a template template
973/// argument instead of a type template argument.
974ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
975 TypeSourceInfo *TInfo;
976 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
977 if (T.isNull())
978 return ParsedTemplateArgument();
979 assert(TInfo && "template argument with no location");
980
981 // If we might have formed a deduced template specialization type, convert
982 // it to a template template argument.
983 if (getLangOpts().CPlusPlus17) {
984 TypeLoc TL = TInfo->getTypeLoc();
985 SourceLocation EllipsisLoc;
986 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
987 EllipsisLoc = PET.getEllipsisLoc();
988 TL = PET.getPatternLoc();
989 }
990
991 CXXScopeSpec SS;
992 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
993 SS.Adopt(ET.getQualifierLoc());
994 TL = ET.getNamedTypeLoc();
995 }
996
997 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
998 TemplateName Name = DTST.getTypePtr()->getTemplateName();
999 if (SS.isSet())
1000 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
1001 /*HasTemplateKeyword*/ false,
1002 Name.getAsTemplateDecl());
1003 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
1004 DTST.getTemplateNameLoc());
1005 if (EllipsisLoc.isValid())
1006 Result = Result.getTemplatePackExpansion(EllipsisLoc);
1007 return Result;
1008 }
1009 }
1010
1011 // This is a normal type template argument. Note, if the type template
1012 // argument is an injected-class-name for a template, it has a dual nature
1013 // and can be used as either a type or a template. We handle that in
1014 // convertTypeTemplateArgumentToTemplate.
1015 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
1016 ParsedType.get().getAsOpaquePtr(),
1017 TInfo->getTypeLoc().getBeginLoc());
1018}
1019
1020/// ActOnTypeParameter - Called when a C++ template type parameter
1021/// (e.g., "typename T") has been parsed. Typename specifies whether
1022/// the keyword "typename" was used to declare the type parameter
1023/// (otherwise, "class" was used), and KeyLoc is the location of the
1024/// "class" or "typename" keyword. ParamName is the name of the
1025/// parameter (NULL indicates an unnamed template parameter) and
1026/// ParamNameLoc is the location of the parameter name (if any).
1027/// If the type parameter has a default argument, it will be added
1028/// later via ActOnTypeParameterDefault.
1029NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
1030 SourceLocation EllipsisLoc,
1031 SourceLocation KeyLoc,
1032 IdentifierInfo *ParamName,
1033 SourceLocation ParamNameLoc,
1034 unsigned Depth, unsigned Position,
1035 SourceLocation EqualLoc,
1036 ParsedType DefaultArg,
1037 bool HasTypeConstraint) {
1038 assert(S->isTemplateParamScope() &&
1039 "Template type parameter not in template parameter scope!");
1040
1041 bool IsParameterPack = EllipsisLoc.isValid();
1042 TemplateTypeParmDecl *Param
1043 = TemplateTypeParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1044 KeyLoc, ParamNameLoc, Depth, Position,
1045 ParamName, Typename, IsParameterPack,
1046 HasTypeConstraint);
1047 Param->setAccess(AS_public);
1048
1049 if (Param->isParameterPack())
1050 if (auto *LSI = getEnclosingLambda())
1051 LSI->LocalPacks.push_back(Param);
1052
1053 if (ParamName) {
1054 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1055
1056 // Add the template parameter into the current scope.
1057 S->AddDecl(Param);
1058 IdResolver.AddDecl(Param);
1059 }
1060
1061 // C++0x [temp.param]p9:
1062 // A default template-argument may be specified for any kind of
1063 // template-parameter that is not a template parameter pack.
1064 if (DefaultArg && IsParameterPack) {
1065 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1066 DefaultArg = nullptr;
1067 }
1068
1069 // Handle the default argument, if provided.
1070 if (DefaultArg) {
1071 TypeSourceInfo *DefaultTInfo;
1072 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1073
1074 assert(DefaultTInfo && "expected source information for type");
1075
1076 // Check for unexpanded parameter packs.
1077 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1078 UPPC_DefaultArgument))
1079 return Param;
1080
1081 // Check the template argument itself.
1082 if (CheckTemplateArgument(Param, DefaultTInfo)) {
1083 Param->setInvalidDecl();
1084 return Param;
1085 }
1086
1087 Param->setDefaultArgument(DefaultTInfo);
1088 }
1089
1090 return Param;
1091}
1092
1093/// Convert the parser's template argument list representation into our form.
1094static TemplateArgumentListInfo
1095makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
1096 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
1097 TemplateId.RAngleLoc);
1098 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
1099 TemplateId.NumArgs);
1100 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
1101 return TemplateArgs;
1102}
1103
1104bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
1105 TemplateIdAnnotation *TypeConstr,
1106 TemplateTypeParmDecl *ConstrainedParameter,
1107 SourceLocation EllipsisLoc) {
1108 ConceptDecl *CD =
1109 cast<ConceptDecl>(TypeConstr->Template.get().getAsTemplateDecl());
1110
1111 // C++2a [temp.param]p4:
1112 // [...] The concept designated by a type-constraint shall be a type
1113 // concept ([temp.concept]).
1114 if (!CD->isTypeConcept()) {
1115 Diag(TypeConstr->TemplateNameLoc,
1116 diag::err_type_constraint_non_type_concept);
1117 return true;
1118 }
1119
1120 bool WereArgsSpecified = TypeConstr->LAngleLoc.isValid();
1121
1122 if (!WereArgsSpecified &&
1123 CD->getTemplateParameters()->getMinRequiredArguments() > 1) {
1124 Diag(TypeConstr->TemplateNameLoc,
1125 diag::err_type_constraint_missing_arguments) << CD;
1126 return true;
1127 }
1128
1129 TemplateArgumentListInfo TemplateArgs;
1130 if (TypeConstr->LAngleLoc.isValid()) {
1131 TemplateArgs =
1132 makeTemplateArgumentListInfo(*this, *TypeConstr);
1133 }
1134 return AttachTypeConstraint(
1135 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
1136 DeclarationNameInfo(DeclarationName(TypeConstr->Name),
1137 TypeConstr->TemplateNameLoc), CD,
1138 TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
1139 ConstrainedParameter, EllipsisLoc);
1140}
1141
1142template<typename ArgumentLocAppender>
1143static ExprResult formImmediatelyDeclaredConstraint(
1144 Sema &S, NestedNameSpecifierLoc NS, DeclarationNameInfo NameInfo,
1145 ConceptDecl *NamedConcept, SourceLocation LAngleLoc,
1146 SourceLocation RAngleLoc, QualType ConstrainedType,
1147 SourceLocation ParamNameLoc, ArgumentLocAppender Appender,
1148 SourceLocation EllipsisLoc) {
1149
1150 TemplateArgumentListInfo ConstraintArgs;
1151 ConstraintArgs.addArgument(
1152 S.getTrivialTemplateArgumentLoc(TemplateArgument(ConstrainedType),
1153 /*NTTPType=*/QualType(), ParamNameLoc));
1154
1155 ConstraintArgs.setRAngleLoc(RAngleLoc);
1156 ConstraintArgs.setLAngleLoc(LAngleLoc);
1157 Appender(ConstraintArgs);
1158
1159 // C++2a [temp.param]p4:
1160 // [...] This constraint-expression E is called the immediately-declared
1161 // constraint of T. [...]
1162 CXXScopeSpec SS;
1163 SS.Adopt(NS);
1164 ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
1165 SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
1166 /*FoundDecl=*/NamedConcept, NamedConcept, &ConstraintArgs);
1167 if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
1168 return ImmediatelyDeclaredConstraint;
1169
1170 // C++2a [temp.param]p4:
1171 // [...] If T is not a pack, then E is E', otherwise E is (E' && ...).
1172 //
1173 // We have the following case:
1174 //
1175 // template<typename T> concept C1 = true;
1176 // template<C1... T> struct s1;
1177 //
1178 // The constraint: (C1<T> && ...)
1179 //
1180 // Note that the type of C1<T> is known to be 'bool', so we don't need to do
1181 // any unqualified lookups for 'operator&&' here.
1182 return S.BuildCXXFoldExpr(/*UnqualifiedLookup=*/nullptr,
1183 /*LParenLoc=*/SourceLocation(),
1184 ImmediatelyDeclaredConstraint.get(), BO_LAnd,
1185 EllipsisLoc, /*RHS=*/nullptr,
1186 /*RParenLoc=*/SourceLocation(),
1187 /*NumExpansions=*/None);
1188}
1189
1190/// Attach a type-constraint to a template parameter.
1191/// \returns true if an error occured. This can happen if the
1192/// immediately-declared constraint could not be formed (e.g. incorrect number
1193/// of arguments for the named concept).
1194bool Sema::AttachTypeConstraint(NestedNameSpecifierLoc NS,
1195 DeclarationNameInfo NameInfo,
1196 ConceptDecl *NamedConcept,
1197 const TemplateArgumentListInfo *TemplateArgs,
1198 TemplateTypeParmDecl *ConstrainedParameter,
1199 SourceLocation EllipsisLoc) {
1200 // C++2a [temp.param]p4:
1201 // [...] If Q is of the form C<A1, ..., An>, then let E' be
1202 // C<T, A1, ..., An>. Otherwise, let E' be C<T>. [...]
1203 const ASTTemplateArgumentListInfo *ArgsAsWritten =
1204 TemplateArgs ? ASTTemplateArgumentListInfo::Create(Context,
1205 *TemplateArgs) : nullptr;
1206
1207 QualType ParamAsArgument(ConstrainedParameter->getTypeForDecl(), 0);
1208
1209 ExprResult ImmediatelyDeclaredConstraint =
1210 formImmediatelyDeclaredConstraint(
1211 *this, NS, NameInfo, NamedConcept,
1212 TemplateArgs ? TemplateArgs->getLAngleLoc() : SourceLocation(),
1213 TemplateArgs ? TemplateArgs->getRAngleLoc() : SourceLocation(),
1214 ParamAsArgument, ConstrainedParameter->getLocation(),
1215 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1216 if (TemplateArgs)
1217 for (const auto &ArgLoc : TemplateArgs->arguments())
1218 ConstraintArgs.addArgument(ArgLoc);
1219 }, EllipsisLoc);
1220 if (ImmediatelyDeclaredConstraint.isInvalid())
1221 return true;
1222
1223 ConstrainedParameter->setTypeConstraint(NS, NameInfo,
1224 /*FoundDecl=*/NamedConcept,
1225 NamedConcept, ArgsAsWritten,
1226 ImmediatelyDeclaredConstraint.get());
1227 return false;
1228}
1229
1230bool Sema::AttachTypeConstraint(AutoTypeLoc TL, NonTypeTemplateParmDecl *NTTP,
1231 SourceLocation EllipsisLoc) {
1232 if (NTTP->getType() != TL.getType() ||
1233 TL.getAutoKeyword() != AutoTypeKeyword::Auto) {
1234 Diag(NTTP->getTypeSourceInfo()->getTypeLoc().getBeginLoc(),
1235 diag::err_unsupported_placeholder_constraint)
1236 << NTTP->getTypeSourceInfo()->getTypeLoc().getSourceRange();
1237 return true;
1238 }
1239 // FIXME: Concepts: This should be the type of the placeholder, but this is
1240 // unclear in the wording right now.
1241 DeclRefExpr *Ref = BuildDeclRefExpr(NTTP, NTTP->getType(), VK_RValue,
1242 NTTP->getLocation());
1243 if (!Ref)
1244 return true;
1245 ExprResult ImmediatelyDeclaredConstraint =
1246 formImmediatelyDeclaredConstraint(
1247 *this, TL.getNestedNameSpecifierLoc(), TL.getConceptNameInfo(),
1248 TL.getNamedConcept(), TL.getLAngleLoc(), TL.getRAngleLoc(),
1249 BuildDecltypeType(Ref, NTTP->getLocation()), NTTP->getLocation(),
1250 [&] (TemplateArgumentListInfo &ConstraintArgs) {
1251 for (unsigned I = 0, C = TL.getNumArgs(); I != C; ++I)
1252 ConstraintArgs.addArgument(TL.getArgLoc(I));
1253 }, EllipsisLoc);
1254 if (ImmediatelyDeclaredConstraint.isInvalid() ||
1255 !ImmediatelyDeclaredConstraint.isUsable())
1256 return true;
1257
1258 NTTP->setPlaceholderTypeConstraint(ImmediatelyDeclaredConstraint.get());
1259 return false;
1260}
1261
1262/// Check that the type of a non-type template parameter is
1263/// well-formed.
1264///
1265/// \returns the (possibly-promoted) parameter type if valid;
1266/// otherwise, produces a diagnostic and returns a NULL type.
1267QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1268 SourceLocation Loc) {
1269 if (TSI->getType()->isUndeducedType()) {
1270 // C++17 [temp.dep.expr]p3:
1271 // An id-expression is type-dependent if it contains
1272 // - an identifier associated by name lookup with a non-type
1273 // template-parameter declared with a type that contains a
1274 // placeholder type (7.1.7.4),
1275 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
1276 }
1277
1278 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1279}
1280
1281/// Require the given type to be a structural type, and diagnose if it is not.
1282///
1283/// \return \c true if an error was produced.
1284bool Sema::RequireStructuralType(QualType T, SourceLocation Loc) {
1285 if (T->isDependentType())
1286 return false;
1287
1288 if (RequireCompleteType(Loc, T, diag::err_template_nontype_parm_incomplete))
1289 return true;
1290
1291 if (T->isStructuralType())
1292 return false;
1293
1294 // Structural types are required to be object types or lvalue references.
1295 if (T->isRValueReferenceType()) {
1296 Diag(Loc, diag::err_template_nontype_parm_rvalue_ref) << T;
1297 return true;
1298 }
1299
1300 // Don't mention structural types in our diagnostic prior to C++20. Also,
1301 // there's not much more we can say about non-scalar non-class types --
1302 // because we can't see functions or arrays here, those can only be language
1303 // extensions.
1304 if (!getLangOpts().CPlusPlus20 ||
1305 (!T->isScalarType() && !T->isRecordType())) {
1306 Diag(Loc, diag::err_template_nontype_parm_bad_type) << T;
1307 return true;
1308 }
1309
1310 // Structural types are required to be literal types.
1311 if (RequireLiteralType(Loc, T, diag::err_template_nontype_parm_not_literal))
1312 return true;
1313
1314 Diag(Loc, diag::err_template_nontype_parm_not_structural) << T;
1315
1316 // Drill down into the reason why the class is non-structural.
1317 while (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
1318 // All members are required to be public and non-mutable, and can't be of
1319 // rvalue reference type. Check these conditions first to prefer a "local"
1320 // reason over a more distant one.
1321 for (const FieldDecl *FD : RD->fields()) {
1322 if (FD->getAccess() != AS_public) {
1323 Diag(FD->getLocation(), diag::note_not_structural_non_public) << T << 0;
1324 return true;
1325 }
1326 if (FD->isMutable()) {
1327 Diag(FD->getLocation(), diag::note_not_structural_mutable_field) << T;
1328 return true;
1329 }
1330 if (FD->getType()->isRValueReferenceType()) {
1331 Diag(FD->getLocation(), diag::note_not_structural_rvalue_ref_field)
1332 << T;
1333 return true;
1334 }
1335 }
1336
1337 // All bases are required to be public.
1338 for (const auto &BaseSpec : RD->bases()) {
1339 if (BaseSpec.getAccessSpecifier() != AS_public) {
1340 Diag(BaseSpec.getBaseTypeLoc(), diag::note_not_structural_non_public)
1341 << T << 1;
1342 return true;
1343 }
1344 }
1345
1346 // All subobjects are required to be of structural types.
1347 SourceLocation SubLoc;
1348 QualType SubType;
1349 int Kind = -1;
1350
1351 for (const FieldDecl *FD : RD->fields()) {
1352 QualType T = Context.getBaseElementType(FD->getType());
1353 if (!T->isStructuralType()) {
1354 SubLoc = FD->getLocation();
1355 SubType = T;
1356 Kind = 0;
1357 break;
1358 }
1359 }
1360
1361 if (Kind == -1) {
1362 for (const auto &BaseSpec : RD->bases()) {
1363 QualType T = BaseSpec.getType();
1364 if (!T->isStructuralType()) {
1365 SubLoc = BaseSpec.getBaseTypeLoc();
1366 SubType = T;
1367 Kind = 1;
1368 break;
1369 }
1370 }
1371 }
1372
1373 assert(Kind != -1 && "couldn't find reason why type is not structural");
1374 Diag(SubLoc, diag::note_not_structural_subobject)
1375 << T << Kind << SubType;
1376 T = SubType;
1377 RD = T->getAsCXXRecordDecl();
1378 }
1379
1380 return true;
1381}
1382
1383QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1384 SourceLocation Loc) {
1385 // We don't allow variably-modified types as the type of non-type template
1386 // parameters.
1387 if (T->isVariablyModifiedType()) {
1388 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1389 << T;
1390 return QualType();
1391 }
1392
1393 // C++ [temp.param]p4:
1394 //
1395 // A non-type template-parameter shall have one of the following
1396 // (optionally cv-qualified) types:
1397 //
1398 // -- integral or enumeration type,
1399 if (T->isIntegralOrEnumerationType() ||
1400 // -- pointer to object or pointer to function,
1401 T->isPointerType() ||
1402 // -- lvalue reference to object or lvalue reference to function,
1403 T->isLValueReferenceType() ||
1404 // -- pointer to member,
1405 T->isMemberPointerType() ||
1406 // -- std::nullptr_t, or
1407 T->isNullPtrType() ||
1408 // -- a type that contains a placeholder type.
1409 T->isUndeducedType()) {
1410 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1411 // are ignored when determining its type.
1412 return T.getUnqualifiedType();
1413 }
1414
1415 // C++ [temp.param]p8:
1416 //
1417 // A non-type template-parameter of type "array of T" or
1418 // "function returning T" is adjusted to be of type "pointer to
1419 // T" or "pointer to function returning T", respectively.
1420 if (T->isArrayType() || T->isFunctionType())
1421 return Context.getDecayedType(T);
1422
1423 // If T is a dependent type, we can't do the check now, so we
1424 // assume that it is well-formed. Note that stripping off the
1425 // qualifiers here is not really correct if T turns out to be
1426 // an array type, but we'll recompute the type everywhere it's
1427 // used during instantiation, so that should be OK. (Using the
1428 // qualified type is equally wrong.)
1429 if (T->isDependentType())
1430 return T.getUnqualifiedType();
1431
1432 // C++20 [temp.param]p6:
1433 // -- a structural type
1434 if (RequireStructuralType(T, Loc))
1435 return QualType();
1436
1437 if (!getLangOpts().CPlusPlus20) {
1438 // FIXME: Consider allowing structural types as an extension in C++17. (In
1439 // earlier language modes, the template argument evaluation rules are too
1440 // inflexible.)
1441 Diag(Loc, diag::err_template_nontype_parm_bad_structural_type) << T;
1442 return QualType();
1443 }
1444
1445 Diag(Loc, diag::warn_cxx17_compat_template_nontype_parm_type) << T;
1446 return T.getUnqualifiedType();
1447}
1448
1449NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1450 unsigned Depth,
1451 unsigned Position,
1452 SourceLocation EqualLoc,
1453 Expr *Default) {
1454 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1455
1456 // Check that we have valid decl-specifiers specified.
1457 auto CheckValidDeclSpecifiers = [this, &D] {
1458 // C++ [temp.param]
1459 // p1
1460 // template-parameter:
1461 // ...
1462 // parameter-declaration
1463 // p2
1464 // ... A storage class shall not be specified in a template-parameter
1465 // declaration.
1466 // [dcl.typedef]p1:
1467 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1468 // of a parameter-declaration
1469 const DeclSpec &DS = D.getDeclSpec();
1470 auto EmitDiag = [this](SourceLocation Loc) {
1471 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1472 << FixItHint::CreateRemoval(Loc);
1473 };
1474 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1475 EmitDiag(DS.getStorageClassSpecLoc());
1476
1477 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1478 EmitDiag(DS.getThreadStorageClassSpecLoc());
1479
1480 // [dcl.inline]p1:
1481 // The inline specifier can be applied only to the declaration or
1482 // definition of a variable or function.
1483
1484 if (DS.isInlineSpecified())
1485 EmitDiag(DS.getInlineSpecLoc());
1486
1487 // [dcl.constexpr]p1:
1488 // The constexpr specifier shall be applied only to the definition of a
1489 // variable or variable template or the declaration of a function or
1490 // function template.
1491
1492 if (DS.hasConstexprSpecifier())
1493 EmitDiag(DS.getConstexprSpecLoc());
1494
1495 // [dcl.fct.spec]p1:
1496 // Function-specifiers can be used only in function declarations.
1497
1498 if (DS.isVirtualSpecified())
1499 EmitDiag(DS.getVirtualSpecLoc());
1500
1501 if (DS.hasExplicitSpecifier())
1502 EmitDiag(DS.getExplicitSpecLoc());
1503
1504 if (DS.isNoreturnSpecified())
1505 EmitDiag(DS.getNoreturnSpecLoc());
1506 };
1507
1508 CheckValidDeclSpecifiers();
1509
1510 if (TInfo->getType()->isUndeducedType()) {
1511 Diag(D.getIdentifierLoc(),
1512 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1513 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1514 }
1515
1516 assert(S->isTemplateParamScope() &&
1517 "Non-type template parameter not in template parameter scope!");
1518 bool Invalid = false;
1519
1520 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1521 if (T.isNull()) {
1522 T = Context.IntTy; // Recover with an 'int' type.
1523 Invalid = true;
1524 }
1525
1526 CheckFunctionOrTemplateParamDeclarator(S, D);
1527
1528 IdentifierInfo *ParamName = D.getIdentifier();
1529 bool IsParameterPack = D.hasEllipsis();
1530 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1531 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1532 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1533 TInfo);
1534 Param->setAccess(AS_public);
1535
1536 if (AutoTypeLoc TL = TInfo->getTypeLoc().getContainedAutoTypeLoc())
1537 if (TL.isConstrained())
1538 if (AttachTypeConstraint(TL, Param, D.getEllipsisLoc()))
1539 Invalid = true;
1540
1541 if (Invalid)
1542 Param->setInvalidDecl();
1543
1544 if (Param->isParameterPack())
1545 if (auto *LSI = getEnclosingLambda())
1546 LSI->LocalPacks.push_back(Param);
1547
1548 if (ParamName) {
1549 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1550 ParamName);
1551
1552 // Add the template parameter into the current scope.
1553 S->AddDecl(Param);
1554 IdResolver.AddDecl(Param);
1555 }
1556
1557 // C++0x [temp.param]p9:
1558 // A default template-argument may be specified for any kind of
1559 // template-parameter that is not a template parameter pack.
1560 if (Default && IsParameterPack) {
1561 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1562 Default = nullptr;
1563 }
1564
1565 // Check the well-formedness of the default template argument, if provided.
1566 if (Default) {
1567 // Check for unexpanded parameter packs.
1568 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1569 return Param;
1570
1571 TemplateArgument Converted;
1572 ExprResult DefaultRes =
1573 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1574 if (DefaultRes.isInvalid()) {
1575 Param->setInvalidDecl();
1576 return Param;
1577 }
1578 Default = DefaultRes.get();
1579
1580 Param->setDefaultArgument(Default);
1581 }
1582
1583 return Param;
1584}
1585
1586/// ActOnTemplateTemplateParameter - Called when a C++ template template
1587/// parameter (e.g. T in template <template \<typename> class T> class array)
1588/// has been parsed. S is the current scope.
1589NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1590 SourceLocation TmpLoc,
1591 TemplateParameterList *Params,
1592 SourceLocation EllipsisLoc,
1593 IdentifierInfo *Name,
1594 SourceLocation NameLoc,
1595 unsigned Depth,
1596 unsigned Position,
1597 SourceLocation EqualLoc,
1598 ParsedTemplateArgument Default) {
1599 assert(S->isTemplateParamScope() &&
1600 "Template template parameter not in template parameter scope!");
1601
1602 // Construct the parameter object.
1603 bool IsParameterPack = EllipsisLoc.isValid();
1604 TemplateTemplateParmDecl *Param =
1605 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1606 NameLoc.isInvalid()? TmpLoc : NameLoc,
1607 Depth, Position, IsParameterPack,
1608 Name, Params);
1609 Param->setAccess(AS_public);
1610
1611 if (Param->isParameterPack())
1612 if (auto *LSI = getEnclosingLambda())
1613 LSI->LocalPacks.push_back(Param);
1614
1615 // If the template template parameter has a name, then link the identifier
1616 // into the scope and lookup mechanisms.
1617 if (Name) {
1618 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1619
1620 S->AddDecl(Param);
1621 IdResolver.AddDecl(Param);
1622 }
1623
1624 if (Params->size() == 0) {
1625 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1626 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1627 Param->setInvalidDecl();
1628 }
1629
1630 // C++0x [temp.param]p9:
1631 // A default template-argument may be specified for any kind of
1632 // template-parameter that is not a template parameter pack.
1633 if (IsParameterPack && !Default.isInvalid()) {
1634 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1635 Default = ParsedTemplateArgument();
1636 }
1637
1638 if (!Default.isInvalid()) {
1639 // Check only that we have a template template argument. We don't want to
1640 // try to check well-formedness now, because our template template parameter
1641 // might have dependent types in its template parameters, which we wouldn't
1642 // be able to match now.
1643 //
1644 // If none of the template template parameter's template arguments mention
1645 // other template parameters, we could actually perform more checking here.
1646 // However, it isn't worth doing.
1647 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1648 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1649 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1650 << DefaultArg.getSourceRange();
1651 return Param;
1652 }
1653
1654 // Check for unexpanded parameter packs.
1655 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1656 DefaultArg.getArgument().getAsTemplate(),
1657 UPPC_DefaultArgument))
1658 return Param;
1659
1660 Param->setDefaultArgument(Context, DefaultArg);
1661 }
1662
1663 return Param;
1664}
1665
1666/// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1667/// constrained by RequiresClause, that contains the template parameters in
1668/// Params.
1669TemplateParameterList *
1670Sema::ActOnTemplateParameterList(unsigned Depth,
1671 SourceLocation ExportLoc,
1672 SourceLocation TemplateLoc,
1673 SourceLocation LAngleLoc,
1674 ArrayRef<NamedDecl *> Params,
1675 SourceLocation RAngleLoc,
1676 Expr *RequiresClause) {
1677 if (ExportLoc.isValid())
1678 Diag(ExportLoc, diag::warn_template_export_unsupported);
1679
1680 return TemplateParameterList::Create(
1681 Context, TemplateLoc, LAngleLoc,
1682 llvm::makeArrayRef(Params.data(), Params.size()),
1683 RAngleLoc, RequiresClause);
1684}
1685
1686static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1687 const CXXScopeSpec &SS) {
1688 if (SS.isSet())
1689 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1690}
1691
1692DeclResult Sema::CheckClassTemplate(
1693 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1694 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1695 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1696 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1697 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1698 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1699 assert(TemplateParams && TemplateParams->size() > 0 &&
1700 "No template parameters");
1701 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1702 bool Invalid = false;
1703
1704 // Check that we can declare a template here.
1705 if (CheckTemplateDeclScope(S, TemplateParams))
1706 return true;
1707
1708 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1709 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1710
1711 // There is no such thing as an unnamed class template.
1712 if (!Name) {
1713 Diag(KWLoc, diag::err_template_unnamed_class);
1714 return true;
1715 }
1716
1717 // Find any previous declaration with this name. For a friend with no
1718 // scope explicitly specified, we only look for tag declarations (per
1719 // C++11 [basic.lookup.elab]p2).
1720 DeclContext *SemanticContext;
1721 LookupResult Previous(*this, Name, NameLoc,
1722 (SS.isEmpty() && TUK == TUK_Friend)
1723 ? LookupTagName : LookupOrdinaryName,
1724 forRedeclarationInCurContext());
1725 if (SS.isNotEmpty() && !SS.isInvalid()) {
1726 SemanticContext = computeDeclContext(SS, true);
1727 if (!SemanticContext) {
1728 // FIXME: Horrible, horrible hack! We can't currently represent this
1729 // in the AST, and historically we have just ignored such friend
1730 // class templates, so don't complain here.
1731 Diag(NameLoc, TUK == TUK_Friend
1732 ? diag::warn_template_qualified_friend_ignored
1733 : diag::err_template_qualified_declarator_no_match)
1734 << SS.getScopeRep() << SS.getRange();
1735 return TUK != TUK_Friend;
1736 }
1737
1738 if (RequireCompleteDeclContext(SS, SemanticContext))
1739 return true;
1740
1741 // If we're adding a template to a dependent context, we may need to
1742 // rebuilding some of the types used within the template parameter list,
1743 // now that we know what the current instantiation is.
1744 if (SemanticContext->isDependentContext()) {
1745 ContextRAII SavedContext(*this, SemanticContext);
1746 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1747 Invalid = true;
1748 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1749 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1750
1751 LookupQualifiedName(Previous, SemanticContext);
1752 } else {
1753 SemanticContext = CurContext;
1754
1755 // C++14 [class.mem]p14:
1756 // If T is the name of a class, then each of the following shall have a
1757 // name different from T:
1758 // -- every member template of class T
1759 if (TUK != TUK_Friend &&
1760 DiagnoseClassNameShadow(SemanticContext,
1761 DeclarationNameInfo(Name, NameLoc)))
1762 return true;
1763
1764 LookupName(Previous, S);
1765 }
1766
1767 if (Previous.isAmbiguous())
1768 return true;
1769
1770 NamedDecl *PrevDecl = nullptr;
1771 if (Previous.begin() != Previous.end())
1772 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1773
1774 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1775 // Maybe we will complain about the shadowed template parameter.
1776 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1777 // Just pretend that we didn't see the previous declaration.
1778 PrevDecl = nullptr;
1779 }
1780
1781 // If there is a previous declaration with the same name, check
1782 // whether this is a valid redeclaration.
1783 ClassTemplateDecl *PrevClassTemplate =
1784 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1785
1786 // We may have found the injected-class-name of a class template,
1787 // class template partial specialization, or class template specialization.
1788 // In these cases, grab the template that is being defined or specialized.
1789 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1790 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1791 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1792 PrevClassTemplate
1793 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1794 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1795 PrevClassTemplate
1796 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1797 ->getSpecializedTemplate();
1798 }
1799 }
1800
1801 if (TUK == TUK_Friend) {
1802 // C++ [namespace.memdef]p3:
1803 // [...] When looking for a prior declaration of a class or a function
1804 // declared as a friend, and when the name of the friend class or
1805 // function is neither a qualified name nor a template-id, scopes outside
1806 // the innermost enclosing namespace scope are not considered.
1807 if (!SS.isSet()) {
1808 DeclContext *OutermostContext = CurContext;
1809 while (!OutermostContext->isFileContext())
1810 OutermostContext = OutermostContext->getLookupParent();
1811
1812 if (PrevDecl &&
1813 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1814 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1815 SemanticContext = PrevDecl->getDeclContext();
1816 } else {
1817 // Declarations in outer scopes don't matter. However, the outermost
1818 // context we computed is the semantic context for our new
1819 // declaration.
1820 PrevDecl = PrevClassTemplate = nullptr;
1821 SemanticContext = OutermostContext;
1822
1823 // Check that the chosen semantic context doesn't already contain a
1824 // declaration of this name as a non-tag type.
1825 Previous.clear(LookupOrdinaryName);
1826 DeclContext *LookupContext = SemanticContext;
1827 while (LookupContext->isTransparentContext())
1828 LookupContext = LookupContext->getLookupParent();
1829 LookupQualifiedName(Previous, LookupContext);
1830
1831 if (Previous.isAmbiguous())
1832 return true;
1833
1834 if (Previous.begin() != Previous.end())
1835 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1836 }
1837 }
1838 } else if (PrevDecl &&
1839 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1840 S, SS.isValid()))
1841 PrevDecl = PrevClassTemplate = nullptr;
1842
1843 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1844 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1845 if (SS.isEmpty() &&
1846 !(PrevClassTemplate &&
1847 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1848 SemanticContext->getRedeclContext()))) {
1849 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1850 Diag(Shadow->getTargetDecl()->getLocation(),
1851 diag::note_using_decl_target);
1852 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1853 // Recover by ignoring the old declaration.
1854 PrevDecl = PrevClassTemplate = nullptr;
1855 }
1856 }
1857
1858 if (PrevClassTemplate) {
1859 // Ensure that the template parameter lists are compatible. Skip this check
1860 // for a friend in a dependent context: the template parameter list itself
1861 // could be dependent.
1862 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1863 !TemplateParameterListsAreEqual(TemplateParams,
1864 PrevClassTemplate->getTemplateParameters(),
1865 /*Complain=*/true,
1866 TPL_TemplateMatch))
1867 return true;
1868
1869 // C++ [temp.class]p4:
1870 // In a redeclaration, partial specialization, explicit
1871 // specialization or explicit instantiation of a class template,
1872 // the class-key shall agree in kind with the original class
1873 // template declaration (7.1.5.3).
1874 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1875 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1876 TUK == TUK_Definition, KWLoc, Name)) {
1877 Diag(KWLoc, diag::err_use_with_wrong_tag)
1878 << Name
1879 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1880 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1881 Kind = PrevRecordDecl->getTagKind();
1882 }
1883
1884 // Check for redefinition of this class template.
1885 if (TUK == TUK_Definition) {
1886 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1887 // If we have a prior definition that is not visible, treat this as
1888 // simply making that previous definition visible.
1889 NamedDecl *Hidden = nullptr;
1890 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1891 SkipBody->ShouldSkip = true;
1892 SkipBody->Previous = Def;
1893 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1894 assert(Tmpl && "original definition of a class template is not a "
1895 "class template?");
1896 makeMergedDefinitionVisible(Hidden);
1897 makeMergedDefinitionVisible(Tmpl);
1898 } else {
1899 Diag(NameLoc, diag::err_redefinition) << Name;
1900 Diag(Def->getLocation(), diag::note_previous_definition);
1901 // FIXME: Would it make sense to try to "forget" the previous
1902 // definition, as part of error recovery?
1903 return true;
1904 }
1905 }
1906 }
1907 } else if (PrevDecl) {
1908 // C++ [temp]p5:
1909 // A class template shall not have the same name as any other
1910 // template, class, function, object, enumeration, enumerator,
1911 // namespace, or type in the same scope (3.3), except as specified
1912 // in (14.5.4).
1913 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1914 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1915 return true;
1916 }
1917
1918 // Check the template parameter list of this declaration, possibly
1919 // merging in the template parameter list from the previous class
1920 // template declaration. Skip this check for a friend in a dependent
1921 // context, because the template parameter list might be dependent.
1922 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1923 CheckTemplateParameterList(
1924 TemplateParams,
1925 PrevClassTemplate
1926 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1927 : nullptr,
1928 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1929 SemanticContext->isDependentContext())
1930 ? TPC_ClassTemplateMember
1931 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1932 SkipBody))
1933 Invalid = true;
1934
1935 if (SS.isSet()) {
1936 // If the name of the template was qualified, we must be defining the
1937 // template out-of-line.
1938 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1939 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1940 : diag::err_member_decl_does_not_match)
1941 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1942 Invalid = true;
1943 }
1944 }
1945
1946 // If this is a templated friend in a dependent context we should not put it
1947 // on the redecl chain. In some cases, the templated friend can be the most
1948 // recent declaration tricking the template instantiator to make substitutions
1949 // there.
1950 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1951 bool ShouldAddRedecl
1952 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1953
1954 CXXRecordDecl *NewClass =
1955 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1956 PrevClassTemplate && ShouldAddRedecl ?
1957 PrevClassTemplate->getTemplatedDecl() : nullptr,
1958 /*DelayTypeCreation=*/true);
1959 SetNestedNameSpecifier(*this, NewClass, SS);
1960 if (NumOuterTemplateParamLists > 0)
1961 NewClass->setTemplateParameterListsInfo(
1962 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1963 NumOuterTemplateParamLists));
1964
1965 // Add alignment attributes if necessary; these attributes are checked when
1966 // the ASTContext lays out the structure.
1967 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1968 AddAlignmentAttributesForRecord(NewClass);
1969 AddMsStructLayoutForRecord(NewClass);
1970 }
1971
1972 ClassTemplateDecl *NewTemplate
1973 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1974 DeclarationName(Name), TemplateParams,
1975 NewClass);
1976
1977 if (ShouldAddRedecl)
1978 NewTemplate->setPreviousDecl(PrevClassTemplate);
1979
1980 NewClass->setDescribedClassTemplate(NewTemplate);
1981
1982 if (ModulePrivateLoc.isValid())
1983 NewTemplate->setModulePrivate();
1984
1985 // Build the type for the class template declaration now.
1986 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1987 T = Context.getInjectedClassNameType(NewClass, T);
1988 assert(T->isDependentType() && "Class template type is not dependent?");
1989 (void)T;
1990
1991 // If we are providing an explicit specialization of a member that is a
1992 // class template, make a note of that.
1993 if (PrevClassTemplate &&
1994 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1995 PrevClassTemplate->setMemberSpecialization();
1996
1997 // Set the access specifier.
1998 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1999 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
2000
2001 // Set the lexical context of these templates
2002 NewClass->setLexicalDeclContext(CurContext);
2003 NewTemplate->setLexicalDeclContext(CurContext);
2004
2005 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
2006 NewClass->startDefinition();
2007
2008 ProcessDeclAttributeList(S, NewClass, Attr);
2009
2010 if (PrevClassTemplate)
2011 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
2012
2013 AddPushedVisibilityAttribute(NewClass);
2014 inferGslOwnerPointerAttribute(NewClass);
2015
2016 if (TUK != TUK_Friend) {
2017 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
2018 Scope *Outer = S;
2019 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
2020 Outer = Outer->getParent();
2021 PushOnScopeChains(NewTemplate, Outer);
2022 } else {
2023 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
2024 NewTemplate->setAccess(PrevClassTemplate->getAccess());
2025 NewClass->setAccess(PrevClassTemplate->getAccess());
2026 }
2027
2028 NewTemplate->setObjectOfFriendDecl();
2029
2030 // Friend templates are visible in fairly strange ways.
2031 if (!CurContext->isDependentContext()) {
2032 DeclContext *DC = SemanticContext->getRedeclContext();
2033 DC->makeDeclVisibleInContext(NewTemplate);
2034 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
2035 PushOnScopeChains(NewTemplate, EnclosingScope,
2036 /* AddToContext = */ false);
2037 }
2038
2039 FriendDecl *Friend = FriendDecl::Create(
2040 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
2041 Friend->setAccess(AS_public);
2042 CurContext->addDecl(Friend);
2043 }
2044
2045 if (PrevClassTemplate)
2046 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
2047
2048 if (Invalid) {
2049 NewTemplate->setInvalidDecl();
2050 NewClass->setInvalidDecl();
2051 }
2052
2053 ActOnDocumentableDecl(NewTemplate);
2054
2055 if (SkipBody && SkipBody->ShouldSkip)
2056 return SkipBody->Previous;
2057
2058 return NewTemplate;
2059}
2060
2061namespace {
2062/// Tree transform to "extract" a transformed type from a class template's
2063/// constructor to a deduction guide.
2064class ExtractTypeForDeductionGuide
2065 : public TreeTransform<ExtractTypeForDeductionGuide> {
2066 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs;
2067
2068public:
2069 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
2070 ExtractTypeForDeductionGuide(
2071 Sema &SemaRef,
2072 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs)
2073 : Base(SemaRef), MaterializedTypedefs(MaterializedTypedefs) {}
2074
2075 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
2076
2077 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
2078 ASTContext &Context = SemaRef.getASTContext();
2079 TypedefNameDecl *OrigDecl = TL.getTypedefNameDecl();
2080 TypedefNameDecl *Decl = OrigDecl;
2081 // Transform the underlying type of the typedef and clone the Decl only if
2082 // the typedef has a dependent context.
2083 if (OrigDecl->getDeclContext()->isDependentContext()) {
2084 TypeLocBuilder InnerTLB;
2085 QualType Transformed =
2086 TransformType(InnerTLB, OrigDecl->getTypeSourceInfo()->getTypeLoc());
2087 TypeSourceInfo *TSI = InnerTLB.getTypeSourceInfo(Context, Transformed);
2088 if (isa<TypeAliasDecl>(OrigDecl))
2089 Decl = TypeAliasDecl::Create(
2090 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2091 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2092 else {
2093 assert(isa<TypedefDecl>(OrigDecl) && "Not a Type alias or typedef");
2094 Decl = TypedefDecl::Create(
2095 Context, Context.getTranslationUnitDecl(), OrigDecl->getBeginLoc(),
2096 OrigDecl->getLocation(), OrigDecl->getIdentifier(), TSI);
2097 }
2098 MaterializedTypedefs.push_back(Decl);
2099 }
2100
2101 QualType TDTy = Context.getTypedefType(Decl);
2102 TypedefTypeLoc TypedefTL = TLB.push<TypedefTypeLoc>(TDTy);
2103 TypedefTL.setNameLoc(TL.getNameLoc());
2104
2105 return TDTy;
2106 }
2107};
2108
2109/// Transform to convert portions of a constructor declaration into the
2110/// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
2111struct ConvertConstructorToDeductionGuideTransform {
2112 ConvertConstructorToDeductionGuideTransform(Sema &S,
2113 ClassTemplateDecl *Template)
2114 : SemaRef(S), Template(Template) {}
2115
2116 Sema &SemaRef;
2117 ClassTemplateDecl *Template;
2118
2119 DeclContext *DC = Template->getDeclContext();
2120 CXXRecordDecl *Primary = Template->getTemplatedDecl();
2121 DeclarationName DeductionGuideName =
2122 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
2123
2124 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
2125
2126 // Index adjustment to apply to convert depth-1 template parameters into
2127 // depth-0 template parameters.
2128 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
2129
2130 /// Transform a constructor declaration into a deduction guide.
2131 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
2132 CXXConstructorDecl *CD) {
2133 SmallVector<TemplateArgument, 16> SubstArgs;
2134
2135 LocalInstantiationScope Scope(SemaRef);
2136
2137 // C++ [over.match.class.deduct]p1:
2138 // -- For each constructor of the class template designated by the
2139 // template-name, a function template with the following properties:
2140
2141 // -- The template parameters are the template parameters of the class
2142 // template followed by the template parameters (including default
2143 // template arguments) of the constructor, if any.
2144 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
2145 if (FTD) {
2146 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
2147 SmallVector<NamedDecl *, 16> AllParams;
2148 AllParams.reserve(TemplateParams->size() + InnerParams->size());
2149 AllParams.insert(AllParams.begin(),
2150 TemplateParams->begin(), TemplateParams->end());
2151 SubstArgs.reserve(InnerParams->size());
2152
2153 // Later template parameters could refer to earlier ones, so build up
2154 // a list of substituted template arguments as we go.
2155 for (NamedDecl *Param : *InnerParams) {
2156 MultiLevelTemplateArgumentList Args;
2157 Args.setKind(TemplateSubstitutionKind::Rewrite);
2158 Args.addOuterTemplateArguments(SubstArgs);
2159 Args.addOuterRetainedLevel();
2160 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
2161 if (!NewParam)
2162 return nullptr;
2163 AllParams.push_back(NewParam);
2164 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
2165 SemaRef.Context.getInjectedTemplateArg(NewParam)));
2166 }
2167 TemplateParams = TemplateParameterList::Create(
2168 SemaRef.Context, InnerParams->getTemplateLoc(),
2169 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
2170 /*FIXME: RequiresClause*/ nullptr);
2171 }
2172
2173 // If we built a new template-parameter-list, track that we need to
2174 // substitute references to the old parameters into references to the
2175 // new ones.
2176 MultiLevelTemplateArgumentList Args;
2177 Args.setKind(TemplateSubstitutionKind::Rewrite);
2178 if (FTD) {
2179 Args.addOuterTemplateArguments(SubstArgs);
2180 Args.addOuterRetainedLevel();
2181 }
2182
2183 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
2184 .getAsAdjusted<FunctionProtoTypeLoc>();
2185 assert(FPTL && "no prototype for constructor declaration");
2186
2187 // Transform the type of the function, adjusting the return type and
2188 // replacing references to the old parameters with references to the
2189 // new ones.
2190 TypeLocBuilder TLB;
2191 SmallVector<ParmVarDecl*, 8> Params;
2192 SmallVector<TypedefNameDecl *, 4> MaterializedTypedefs;
2193 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args,
2194 MaterializedTypedefs);
2195 if (NewType.isNull())
2196 return nullptr;
2197 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
2198
2199 return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
2200 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
2201 CD->getEndLoc(), MaterializedTypedefs);
2202 }
2203
2204 /// Build a deduction guide with the specified parameter types.
2205 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
2206 SourceLocation Loc = Template->getLocation();
2207
2208 // Build the requested type.
2209 FunctionProtoType::ExtProtoInfo EPI;
2210 EPI.HasTrailingReturn = true;
2211 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
2212 DeductionGuideName, EPI);
2213 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
2214
2215 FunctionProtoTypeLoc FPTL =
2216 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
2217
2218 // Build the parameters, needed during deduction / substitution.
2219 SmallVector<ParmVarDecl*, 4> Params;
2220 for (auto T : ParamTypes) {
2221 ParmVarDecl *NewParam = ParmVarDecl::Create(
2222 SemaRef.Context, DC, Loc, Loc, nullptr, T,
2223 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
2224 NewParam->setScopeInfo(0, Params.size());
2225 FPTL.setParam(Params.size(), NewParam);
2226 Params.push_back(NewParam);
2227 }
2228
2229 return buildDeductionGuide(Template->getTemplateParameters(),
2230 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
2231 }
2232
2233private:
2234 /// Transform a constructor template parameter into a deduction guide template
2235 /// parameter, rebuilding any internal references to earlier parameters and
2236 /// renumbering as we go.
2237 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
2238 MultiLevelTemplateArgumentList &Args) {
2239 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
2240 // TemplateTypeParmDecl's index cannot be changed after creation, so
2241 // substitute it directly.
2242 auto *NewTTP = TemplateTypeParmDecl::Create(
2243 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
2244 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
2245 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
2246 TTP->isParameterPack(), TTP->hasTypeConstraint(),
2247 TTP->isExpandedParameterPack() ?
2248 llvm::Optional<unsigned>(TTP->getNumExpansionParameters()) : None);
2249 if (const auto *TC = TTP->getTypeConstraint()) {
2250 TemplateArgumentListInfo TransformedArgs;
2251 const auto *ArgsAsWritten = TC->getTemplateArgsAsWritten();
2252 if (!ArgsAsWritten ||
2253 SemaRef.Subst(ArgsAsWritten->getTemplateArgs(),
2254 ArgsAsWritten->NumTemplateArgs, TransformedArgs,
2255 Args))
2256 SemaRef.AttachTypeConstraint(
2257 TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
2258 TC->getNamedConcept(), ArgsAsWritten ? &TransformedArgs : nullptr,
2259 NewTTP,
2260 NewTTP->isParameterPack()
2261 ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
2262 ->getEllipsisLoc()
2263 : SourceLocation());
2264 }
2265 if (TTP->hasDefaultArgument()) {
2266 TypeSourceInfo *InstantiatedDefaultArg =
2267 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
2268 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
2269 if (InstantiatedDefaultArg)
2270 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
2271 }
2272 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
2273 NewTTP);
2274 return NewTTP;
2275 }
2276
2277 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
2278 return transformTemplateParameterImpl(TTP, Args);
2279
2280 return transformTemplateParameterImpl(
2281 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
2282 }
2283 template<typename TemplateParmDecl>
2284 TemplateParmDecl *
2285 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
2286 MultiLevelTemplateArgumentList &Args) {
2287 // Ask the template instantiator to do the heavy lifting for us, then adjust
2288 // the index of the parameter once it's done.
2289 auto *NewParam =
2290 cast<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
2291 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
2292 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
2293 return NewParam;
2294 }
2295
2296 QualType transformFunctionProtoType(
2297 TypeLocBuilder &TLB, FunctionProtoTypeLoc TL,
2298 SmallVectorImpl<ParmVarDecl *> &Params,
2299 MultiLevelTemplateArgumentList &Args,
2300 SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2301 SmallVector<QualType, 4> ParamTypes;
2302 const FunctionProtoType *T = TL.getTypePtr();
2303
2304 // -- The types of the function parameters are those of the constructor.
2305 for (auto *OldParam : TL.getParams()) {
2306 ParmVarDecl *NewParam =
2307 transformFunctionTypeParam(OldParam, Args, MaterializedTypedefs);
2308 if (!NewParam)
2309 return QualType();
2310 ParamTypes.push_back(NewParam->getType());
2311 Params.push_back(NewParam);
2312 }
2313
2314 // -- The return type is the class template specialization designated by
2315 // the template-name and template arguments corresponding to the
2316 // template parameters obtained from the class template.
2317 //
2318 // We use the injected-class-name type of the primary template instead.
2319 // This has the convenient property that it is different from any type that
2320 // the user can write in a deduction-guide (because they cannot enter the
2321 // context of the template), so implicit deduction guides can never collide
2322 // with explicit ones.
2323 QualType ReturnType = DeducedType;
2324 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
2325
2326 // Resolving a wording defect, we also inherit the variadicness of the
2327 // constructor.
2328 FunctionProtoType::ExtProtoInfo EPI;
2329 EPI.Variadic = T->isVariadic();
2330 EPI.HasTrailingReturn = true;
2331
2332 QualType Result = SemaRef.BuildFunctionType(
2333 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
2334 if (Result.isNull())
2335 return QualType();
2336
2337 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
2338 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
2339 NewTL.setLParenLoc(TL.getLParenLoc());
2340 NewTL.setRParenLoc(TL.getRParenLoc());
2341 NewTL.setExceptionSpecRange(SourceRange());
2342 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
2343 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
2344 NewTL.setParam(I, Params[I]);
2345
2346 return Result;
2347 }
2348
2349 ParmVarDecl *transformFunctionTypeParam(
2350 ParmVarDecl *OldParam, MultiLevelTemplateArgumentList &Args,
2351 llvm::SmallVectorImpl<TypedefNameDecl *> &MaterializedTypedefs) {
2352 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
2353 TypeSourceInfo *NewDI;
2354 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
2355 // Expand out the one and only element in each inner pack.
2356 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
2357 NewDI =
2358 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
2359 OldParam->getLocation(), OldParam->getDeclName());
2360 if (!NewDI) return nullptr;
2361 NewDI =
2362 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
2363 PackTL.getTypePtr()->getNumExpansions());
2364 } else
2365 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
2366 OldParam->getDeclName());
2367 if (!NewDI)
2368 return nullptr;
2369
2370 // Extract the type. This (for instance) replaces references to typedef
2371 // members of the current instantiations with the definitions of those
2372 // typedefs, avoiding triggering instantiation of the deduced type during
2373 // deduction.
2374 NewDI = ExtractTypeForDeductionGuide(SemaRef, MaterializedTypedefs)
2375 .transform(NewDI);
2376
2377 // Resolving a wording defect, we also inherit default arguments from the
2378 // constructor.
2379 ExprResult NewDefArg;
2380 if (OldParam->hasDefaultArg()) {
2381 // We don't care what the value is (we won't use it); just create a
2382 // placeholder to indicate there is a default argument.
2383 QualType ParamTy = NewDI->getType();
2384 NewDefArg = new (SemaRef.Context)
2385 OpaqueValueExpr(OldParam->getDefaultArg()->getBeginLoc(),
2386 ParamTy.getNonLValueExprType(SemaRef.Context),
2387 ParamTy->isLValueReferenceType() ? VK_LValue :
2388 ParamTy->isRValueReferenceType() ? VK_XValue :
2389 VK_RValue);
2390 }
2391
2392 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
2393 OldParam->getInnerLocStart(),
2394 OldParam->getLocation(),
2395 OldParam->getIdentifier(),
2396 NewDI->getType(),
2397 NewDI,
2398 OldParam->getStorageClass(),
2399 NewDefArg.get());
2400 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
2401 OldParam->getFunctionScopeIndex());
2402 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2403 return NewParam;
2404 }
2405
2406 FunctionTemplateDecl *buildDeductionGuide(
2407 TemplateParameterList *TemplateParams, ExplicitSpecifier ES,
2408 TypeSourceInfo *TInfo, SourceLocation LocStart, SourceLocation Loc,
2409 SourceLocation LocEnd,
2410 llvm::ArrayRef<TypedefNameDecl *> MaterializedTypedefs = {}) {
2411 DeclarationNameInfo Name(DeductionGuideName, Loc);
2412 ArrayRef<ParmVarDecl *> Params =
2413 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2414
2415 // Build the implicit deduction guide template.
2416 auto *Guide =
2417 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2418 TInfo->getType(), TInfo, LocEnd);
2419 Guide->setImplicit();
2420 Guide->setParams(Params);
2421
2422 for (auto *Param : Params)
2423 Param->setDeclContext(Guide);
2424 for (auto *TD : MaterializedTypedefs)
2425 TD->setDeclContext(Guide);
2426
2427 auto *GuideTemplate = FunctionTemplateDecl::Create(
2428 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2429 GuideTemplate->setImplicit();
2430 Guide->setDescribedFunctionTemplate(GuideTemplate);
2431
2432 if (isa<CXXRecordDecl>(DC)) {
2433 Guide->setAccess(AS_public);
2434 GuideTemplate->setAccess(AS_public);
2435 }
2436
2437 DC->addDecl(GuideTemplate);
2438 return GuideTemplate;
2439 }
2440};
2441}
2442
2443void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2444 SourceLocation Loc) {
2445 if (CXXRecordDecl *DefRecord =
2446 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2447 TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
2448 Template = DescribedTemplate ? DescribedTemplate : Template;
2449 }
2450
2451 DeclContext *DC = Template->getDeclContext();
2452 if (DC->isDependentContext())
2453 return;
2454
2455 ConvertConstructorToDeductionGuideTransform Transform(
2456 *this, cast<ClassTemplateDecl>(Template));
2457 if (!isCompleteType(Loc, Transform.DeducedType))
2458 return;
2459
2460 // Check whether we've already declared deduction guides for this template.
2461 // FIXME: Consider storing a flag on the template to indicate this.
2462 auto Existing = DC->lookup(Transform.DeductionGuideName);
2463 for (auto *D : Existing)
2464 if (D->isImplicit())
2465 return;
2466
2467 // In case we were expanding a pack when we attempted to declare deduction
2468 // guides, turn off pack expansion for everything we're about to do.
2469 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2470 // Create a template instantiation record to track the "instantiation" of
2471 // constructors into deduction guides.
2472 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2473 // this substitution process actually fail?
2474 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2475 if (BuildingDeductionGuides.isInvalid())
2476 return;
2477
2478 // Convert declared constructors into deduction guide templates.
2479 // FIXME: Skip constructors for which deduction must necessarily fail (those
2480 // for which some class template parameter without a default argument never
2481 // appears in a deduced context).
2482 bool AddedAny = false;
2483 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2484 D = D->getUnderlyingDecl();
2485 if (D->isInvalidDecl() || D->isImplicit())
2486 continue;
2487 D = cast<NamedDecl>(D->getCanonicalDecl());
2488
2489 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2490 auto *CD =
2491 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2492 // Class-scope explicit specializations (MS extension) do not result in
2493 // deduction guides.
2494 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2495 continue;
2496
2497 Transform.transformConstructor(FTD, CD);
2498 AddedAny = true;
2499 }
2500
2501 // C++17 [over.match.class.deduct]
2502 // -- If C is not defined or does not declare any constructors, an
2503 // additional function template derived as above from a hypothetical
2504 // constructor C().
2505 if (!AddedAny)
2506 Transform.buildSimpleDeductionGuide(None);
2507
2508 // -- An additional function template derived as above from a hypothetical
2509 // constructor C(C), called the copy deduction candidate.
2510 cast<CXXDeductionGuideDecl>(
2511 cast<FunctionTemplateDecl>(
2512 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2513 ->getTemplatedDecl())
2514 ->setIsCopyDeductionCandidate();
2515}
2516
2517/// Diagnose the presence of a default template argument on a
2518/// template parameter, which is ill-formed in certain contexts.
2519///
2520/// \returns true if the default template argument should be dropped.
2521static bool DiagnoseDefaultTemplateArgument(Sema &S,
2522 Sema::TemplateParamListContext TPC,
2523 SourceLocation ParamLoc,
2524 SourceRange DefArgRange) {
2525 switch (TPC) {
2526 case Sema::TPC_ClassTemplate:
2527 case Sema::TPC_VarTemplate:
2528 case Sema::TPC_TypeAliasTemplate:
2529 return false;
2530
2531 case Sema::TPC_FunctionTemplate:
2532 case Sema::TPC_FriendFunctionTemplateDefinition:
2533 // C++ [temp.param]p9:
2534 // A default template-argument shall not be specified in a
2535 // function template declaration or a function template
2536 // definition [...]
2537 // If a friend function template declaration specifies a default
2538 // template-argument, that declaration shall be a definition and shall be
2539 // the only declaration of the function template in the translation unit.
2540 // (C++98/03 doesn't have this wording; see DR226).
2541 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2542 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2543 : diag::ext_template_parameter_default_in_function_template)
2544 << DefArgRange;
2545 return false;
2546
2547 case Sema::TPC_ClassTemplateMember:
2548 // C++0x [temp.param]p9:
2549 // A default template-argument shall not be specified in the
2550 // template-parameter-lists of the definition of a member of a
2551 // class template that appears outside of the member's class.
2552 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2553 << DefArgRange;
2554 return true;
2555
2556 case Sema::TPC_FriendClassTemplate:
2557 case Sema::TPC_FriendFunctionTemplate:
2558 // C++ [temp.param]p9:
2559 // A default template-argument shall not be specified in a
2560 // friend template declaration.
2561 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2562 << DefArgRange;
2563 return true;
2564
2565 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2566 // for friend function templates if there is only a single
2567 // declaration (and it is a definition). Strange!
2568 }
2569
2570 llvm_unreachable("Invalid TemplateParamListContext!");
2571}
2572
2573/// Check for unexpanded parameter packs within the template parameters
2574/// of a template template parameter, recursively.
2575static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2576 TemplateTemplateParmDecl *TTP) {
2577 // A template template parameter which is a parameter pack is also a pack
2578 // expansion.
2579 if (TTP->isParameterPack())
2580 return false;
2581
2582 TemplateParameterList *Params = TTP->getTemplateParameters();
2583 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2584 NamedDecl *P = Params->getParam(I);
2585 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
2586 if (!TTP->isParameterPack())
2587 if (const TypeConstraint *TC = TTP->getTypeConstraint())
2588 if (TC->hasExplicitTemplateArgs())
2589 for (auto &ArgLoc : TC->getTemplateArgsAsWritten()->arguments())
2590 if (S.DiagnoseUnexpandedParameterPack(ArgLoc,
2591 Sema::UPPC_TypeConstraint))
2592 return true;
2593 continue;
2594 }
2595
2596 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2597 if (!NTTP->isParameterPack() &&
2598 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2599 NTTP->getTypeSourceInfo(),
2600 Sema::UPPC_NonTypeTemplateParameterType))
2601 return true;
2602
2603 continue;
2604 }
2605
2606 if (TemplateTemplateParmDecl *InnerTTP
2607 = dyn_cast<TemplateTemplateParmDecl>(P))
2608 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2609 return true;
2610 }
2611
2612 return false;
2613}
2614
2615/// Checks the validity of a template parameter list, possibly
2616/// considering the template parameter list from a previous
2617/// declaration.
2618///
2619/// If an "old" template parameter list is provided, it must be
2620/// equivalent (per TemplateParameterListsAreEqual) to the "new"
2621/// template parameter list.
2622///
2623/// \param NewParams Template parameter list for a new template
2624/// declaration. This template parameter list will be updated with any
2625/// default arguments that are carried through from the previous
2626/// template parameter list.
2627///
2628/// \param OldParams If provided, template parameter list from a
2629/// previous declaration of the same template. Default template
2630/// arguments will be merged from the old template parameter list to
2631/// the new template parameter list.
2632///
2633/// \param TPC Describes the context in which we are checking the given
2634/// template parameter list.
2635///
2636/// \param SkipBody If we might have already made a prior merged definition
2637/// of this template visible, the corresponding body-skipping information.
2638/// Default argument redefinition is not an error when skipping such a body,
2639/// because (under the ODR) we can assume the default arguments are the same
2640/// as the prior merged definition.
2641///
2642/// \returns true if an error occurred, false otherwise.
2643bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2644 TemplateParameterList *OldParams,
2645 TemplateParamListContext TPC,
2646 SkipBodyInfo *SkipBody) {
2647 bool Invalid = false;
2648
2649 // C++ [temp.param]p10:
2650 // The set of default template-arguments available for use with a
2651 // template declaration or definition is obtained by merging the
2652 // default arguments from the definition (if in scope) and all
2653 // declarations in scope in the same way default function
2654 // arguments are (8.3.6).
2655 bool SawDefaultArgument = false;
2656 SourceLocation PreviousDefaultArgLoc;
2657
2658 // Dummy initialization to avoid warnings.
2659 TemplateParameterList::iterator OldParam = NewParams->end();
2660 if (OldParams)
2661 OldParam = OldParams->begin();
2662
2663 bool RemoveDefaultArguments = false;
2664 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2665 NewParamEnd = NewParams->end();
2666 NewParam != NewParamEnd; ++NewParam) {
2667 // Variables used to diagnose redundant default arguments
2668 bool RedundantDefaultArg = false;
2669 SourceLocation OldDefaultLoc;
2670 SourceLocation NewDefaultLoc;
2671
2672 // Variable used to diagnose missing default arguments
2673 bool MissingDefaultArg = false;
2674
2675 // Variable used to diagnose non-final parameter packs
2676 bool SawParameterPack = false;
2677
2678 if (TemplateTypeParmDecl *NewTypeParm
2679 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2680 // Check the presence of a default argument here.
2681 if (NewTypeParm->hasDefaultArgument() &&
2682 DiagnoseDefaultTemplateArgument(*this, TPC,
2683 NewTypeParm->getLocation(),
2684 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2685 .getSourceRange()))
2686 NewTypeParm->removeDefaultArgument();
2687
2688 // Merge default arguments for template type parameters.
2689 TemplateTypeParmDecl *OldTypeParm
2690 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2691 if (NewTypeParm->isParameterPack()) {
2692 assert(!NewTypeParm->hasDefaultArgument() &&
2693 "Parameter packs can't have a default argument!");
2694 SawParameterPack = true;
2695 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2696 NewTypeParm->hasDefaultArgument() &&
2697 (!SkipBody || !SkipBody->ShouldSkip)) {
2698 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2699 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2700 SawDefaultArgument = true;
2701 RedundantDefaultArg = true;
2702 PreviousDefaultArgLoc = NewDefaultLoc;
2703 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2704 // Merge the default argument from the old declaration to the
2705 // new declaration.
2706 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2707 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2708 } else if (NewTypeParm->hasDefaultArgument()) {
2709 SawDefaultArgument = true;
2710 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2711 } else if (SawDefaultArgument)
2712 MissingDefaultArg = true;
2713 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2714 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2715 // Check for unexpanded parameter packs.
2716 if (!NewNonTypeParm->isParameterPack() &&
2717 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2718 NewNonTypeParm->getTypeSourceInfo(),
2719 UPPC_NonTypeTemplateParameterType)) {
2720 Invalid = true;
2721 continue;
2722 }
2723
2724 // Check the presence of a default argument here.
2725 if (NewNonTypeParm->hasDefaultArgument() &&
2726 DiagnoseDefaultTemplateArgument(*this, TPC,
2727 NewNonTypeParm->getLocation(),
2728 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2729 NewNonTypeParm->removeDefaultArgument();
2730 }
2731
2732 // Merge default arguments for non-type template parameters
2733 NonTypeTemplateParmDecl *OldNonTypeParm
2734 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2735 if (NewNonTypeParm->isParameterPack()) {
2736 assert(!NewNonTypeParm->hasDefaultArgument() &&
2737 "Parameter packs can't have a default argument!");
2738 if (!NewNonTypeParm->isPackExpansion())
2739 SawParameterPack = true;
2740 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2741 NewNonTypeParm->hasDefaultArgument() &&
2742 (!SkipBody || !SkipBody->ShouldSkip)) {
2743 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2744 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2745 SawDefaultArgument = true;
2746 RedundantDefaultArg = true;
2747 PreviousDefaultArgLoc = NewDefaultLoc;
2748 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2749 // Merge the default argument from the old declaration to the
2750 // new declaration.
2751 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2752 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2753 } else if (NewNonTypeParm->hasDefaultArgument()) {
2754 SawDefaultArgument = true;
2755 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2756 } else if (SawDefaultArgument)
2757 MissingDefaultArg = true;
2758 } else {
2759 TemplateTemplateParmDecl *NewTemplateParm
2760 = cast<TemplateTemplateParmDecl>(*NewParam);
2761
2762 // Check for unexpanded parameter packs, recursively.
2763 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2764 Invalid = true;
2765 continue;
2766 }
2767
2768 // Check the presence of a default argument here.
2769 if (NewTemplateParm->hasDefaultArgument() &&
2770 DiagnoseDefaultTemplateArgument(*this, TPC,
2771 NewTemplateParm->getLocation(),
2772 NewTemplateParm->getDefaultArgument().getSourceRange()))
2773 NewTemplateParm->removeDefaultArgument();
2774
2775 // Merge default arguments for template template parameters
2776 TemplateTemplateParmDecl *OldTemplateParm
2777 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2778 if (NewTemplateParm->isParameterPack()) {
2779 assert(!NewTemplateParm->hasDefaultArgument() &&
2780 "Parameter packs can't have a default argument!");
2781 if (!NewTemplateParm->isPackExpansion())
2782 SawParameterPack = true;
2783 } else if (OldTemplateParm &&
2784 hasVisibleDefaultArgument(OldTemplateParm) &&
2785 NewTemplateParm->hasDefaultArgument() &&
2786 (!SkipBody || !SkipBody->ShouldSkip)) {
2787 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2788 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2789 SawDefaultArgument = true;
2790 RedundantDefaultArg = true;
2791 PreviousDefaultArgLoc = NewDefaultLoc;
2792 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2793 // Merge the default argument from the old declaration to the
2794 // new declaration.
2795 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2796 PreviousDefaultArgLoc
2797 = OldTemplateParm->getDefaultArgument().getLocation();
2798 } else if (NewTemplateParm->hasDefaultArgument()) {
2799 SawDefaultArgument = true;
2800 PreviousDefaultArgLoc
2801 = NewTemplateParm->getDefaultArgument().getLocation();
2802 } else if (SawDefaultArgument)
2803 MissingDefaultArg = true;
2804 }
2805
2806 // C++11 [temp.param]p11:
2807 // If a template parameter of a primary class template or alias template
2808 // is a template parameter pack, it shall be the last template parameter.
2809 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2810 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2811 TPC == TPC_TypeAliasTemplate)) {
2812 Diag((*NewParam)->getLocation(),
2813 diag::err_template_param_pack_must_be_last_template_parameter);
2814 Invalid = true;
2815 }
2816
2817 if (RedundantDefaultArg) {
2818 // C++ [temp.param]p12:
2819 // A template-parameter shall not be given default arguments
2820 // by two different declarations in the same scope.
2821 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2822 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2823 Invalid = true;
2824 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2825 // C++ [temp.param]p11:
2826 // If a template-parameter of a class template has a default
2827 // template-argument, each subsequent template-parameter shall either
2828 // have a default template-argument supplied or be a template parameter
2829 // pack.
2830 Diag((*NewParam)->getLocation(),
2831 diag::err_template_param_default_arg_missing);
2832 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2833 Invalid = true;
2834 RemoveDefaultArguments = true;
2835 }
2836
2837 // If we have an old template parameter list that we're merging
2838 // in, move on to the next parameter.
2839 if (OldParams)
2840 ++OldParam;
2841 }
2842
2843 // We were missing some default arguments at the end of the list, so remove
2844 // all of the default arguments.
2845 if (RemoveDefaultArguments) {
2846 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2847 NewParamEnd = NewParams->end();
2848 NewParam != NewParamEnd; ++NewParam) {
2849 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2850 TTP->removeDefaultArgument();
2851 else if (NonTypeTemplateParmDecl *NTTP
2852 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2853 NTTP->removeDefaultArgument();
2854 else
2855 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2856 }
2857 }
2858
2859 return Invalid;
2860}
2861
2862namespace {
2863
2864/// A class which looks for a use of a certain level of template
2865/// parameter.
2866struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2867 typedef RecursiveASTVisitor<DependencyChecker> super;
2868
2869 unsigned Depth;
2870
2871 // Whether we're looking for a use of a template parameter that makes the
2872 // overall construct type-dependent / a dependent type. This is strictly
2873 // best-effort for now; we may fail to match at all for a dependent type
2874 // in some cases if this is set.
2875 bool IgnoreNonTypeDependent;
2876
2877 bool Match;
2878 SourceLocation MatchLoc;
2879
2880 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2881 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2882 Match(false) {}
2883
2884 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2885 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2886 NamedDecl *ND = Params->getParam(0);
2887 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2888 Depth = PD->getDepth();
2889 } else if (NonTypeTemplateParmDecl *PD =
2890 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2891 Depth = PD->getDepth();
2892 } else {
2893 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2894 }
2895 }
2896
2897 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2898 if (ParmDepth >= Depth) {
2899 Match = true;
2900 MatchLoc = Loc;
2901 return true;
2902 }
2903 return false;
2904 }
2905
2906 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2907 // Prune out non-type-dependent expressions if requested. This can
2908 // sometimes result in us failing to find a template parameter reference
2909 // (if a value-dependent expression creates a dependent type), but this
2910 // mode is best-effort only.
2911 if (auto *E = dyn_cast_or_null<Expr>(S))
2912 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2913 return true;
2914 return super::TraverseStmt(S, Q);
2915 }
2916
2917 bool TraverseTypeLoc(TypeLoc TL) {
2918 if (IgnoreNonTypeDependent && !TL.isNull() &&
2919 !TL.getType()->isDependentType())
2920 return true;
2921 return super::TraverseTypeLoc(TL);
2922 }
2923
2924 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2925 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2926 }
2927
2928 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2929 // For a best-effort search, keep looking until we find a location.
2930 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2931 }
2932
2933 bool TraverseTemplateName(TemplateName N) {
2934 if (TemplateTemplateParmDecl *PD =
2935 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2936 if (Matches(PD->getDepth()))
2937 return false;
2938 return super::TraverseTemplateName(N);
2939 }
2940
2941 bool VisitDeclRefExpr(DeclRefExpr *E) {
2942 if (NonTypeTemplateParmDecl *PD =
2943 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2944 if (Matches(PD->getDepth(), E->getExprLoc()))
2945 return false;
2946 return super::VisitDeclRefExpr(E);
2947 }
2948
2949 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2950 return TraverseType(T->getReplacementType());
2951 }
2952
2953 bool
2954 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2955 return TraverseTemplateArgument(T->getArgumentPack());
2956 }
2957
2958 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2959 return TraverseType(T->getInjectedSpecializationType());
2960 }
2961};
2962} // end anonymous namespace
2963
2964/// Determines whether a given type depends on the given parameter
2965/// list.
2966static bool
2967DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2968 if (!Params->size())
2969 return false;
2970
2971 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2972 Checker.TraverseType(T);
2973 return Checker.Match;
2974}
2975
2976// Find the source range corresponding to the named type in the given
2977// nested-name-specifier, if any.
2978static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2979 QualType T,
2980 const CXXScopeSpec &SS) {
2981 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2982 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2983 if (const Type *CurType = NNS->getAsType()) {
2984 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2985 return NNSLoc.getTypeLoc().getSourceRange();
2986 } else
2987 break;
2988
2989 NNSLoc = NNSLoc.getPrefix();
2990 }
2991
2992 return SourceRange();
2993}
2994
2995/// Match the given template parameter lists to the given scope
2996/// specifier, returning the template parameter list that applies to the
2997/// name.
2998///
2999/// \param DeclStartLoc the start of the declaration that has a scope
3000/// specifier or a template parameter list.
3001///
3002/// \param DeclLoc The location of the declaration itself.
3003///
3004/// \param SS the scope specifier that will be matched to the given template
3005/// parameter lists. This scope specifier precedes a qualified name that is
3006/// being declared.
3007///
3008/// \param TemplateId The template-id following the scope specifier, if there
3009/// is one. Used to check for a missing 'template<>'.
3010///
3011/// \param ParamLists the template parameter lists, from the outermost to the
3012/// innermost template parameter lists.
3013///
3014/// \param IsFriend Whether to apply the slightly different rules for
3015/// matching template parameters to scope specifiers in friend
3016/// declarations.
3017///
3018/// \param IsMemberSpecialization will be set true if the scope specifier
3019/// denotes a fully-specialized type, and therefore this is a declaration of
3020/// a member specialization.
3021///
3022/// \returns the template parameter list, if any, that corresponds to the
3023/// name that is preceded by the scope specifier @p SS. This template
3024/// parameter list may have template parameters (if we're declaring a
3025/// template) or may have no template parameters (if we're declaring a
3026/// template specialization), or may be NULL (if what we're declaring isn't
3027/// itself a template).
3028TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
3029 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
3030 TemplateIdAnnotation *TemplateId,
3031 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
3032 bool &IsMemberSpecialization, bool &Invalid, bool SuppressDiagnostic) {
3033 IsMemberSpecialization = false;
3034 Invalid = false;
3035
3036 // The sequence of nested types to which we will match up the template
3037 // parameter lists. We first build this list by starting with the type named
3038 // by the nested-name-specifier and walking out until we run out of types.
3039 SmallVector<QualType, 4> NestedTypes;
3040 QualType T;
3041 if (SS.getScopeRep()) {
3042 if (CXXRecordDecl *Record
3043 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
3044 T = Context.getTypeDeclType(Record);
3045 else
3046 T = QualType(SS.getScopeRep()->getAsType(), 0);
3047 }
3048
3049 // If we found an explicit specialization that prevents us from needing
3050 // 'template<>' headers, this will be set to the location of that
3051 // explicit specialization.
3052 SourceLocation ExplicitSpecLoc;
3053
3054 while (!T.isNull()) {
3055 NestedTypes.push_back(T);
3056
3057 // Retrieve the parent of a record type.
3058 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3059 // If this type is an explicit specialization, we're done.
3060 if (ClassTemplateSpecializationDecl *Spec
3061 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3062 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
3063 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
3064 ExplicitSpecLoc = Spec->getLocation();
3065 break;
3066 }
3067 } else if (Record->getTemplateSpecializationKind()
3068 == TSK_ExplicitSpecialization) {
3069 ExplicitSpecLoc = Record->getLocation();
3070 break;
3071 }
3072
3073 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
3074 T = Context.getTypeDeclType(Parent);
3075 else
3076 T = QualType();
3077 continue;
3078 }
3079
3080 if (const TemplateSpecializationType *TST
3081 = T->getAs<TemplateSpecializationType>()) {
3082 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3083 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
3084 T = Context.getTypeDeclType(Parent);
3085 else
3086 T = QualType();
3087 continue;
3088 }
3089 }
3090
3091 // Look one step prior in a dependent template specialization type.
3092 if (const DependentTemplateSpecializationType *DependentTST
3093 = T->getAs<DependentTemplateSpecializationType>()) {
3094 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
3095 T = QualType(NNS->getAsType(), 0);
3096 else
3097 T = QualType();
3098 continue;
3099 }
3100
3101 // Look one step prior in a dependent name type.
3102 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
3103 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
3104 T = QualType(NNS->getAsType(), 0);
3105 else
3106 T = QualType();
3107 continue;
3108 }
3109
3110 // Retrieve the parent of an enumeration type.
3111 if (const EnumType *EnumT = T->getAs<EnumType>()) {
3112 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
3113 // check here.
3114 EnumDecl *Enum = EnumT->getDecl();
3115
3116 // Get to the parent type.
3117 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
3118 T = Context.getTypeDeclType(Parent);
3119 else
3120 T = QualType();
3121 continue;
3122 }
3123
3124 T = QualType();
3125 }
3126 // Reverse the nested types list, since we want to traverse from the outermost
3127 // to the innermost while checking template-parameter-lists.
3128 std::reverse(NestedTypes.begin(), NestedTypes.end());
3129
3130 // C++0x [temp.expl.spec]p17:
3131 // A member or a member template may be nested within many
3132 // enclosing class templates. In an explicit specialization for
3133 // such a member, the member declaration shall be preceded by a
3134 // template<> for each enclosing class template that is
3135 // explicitly specialized.
3136 bool SawNonEmptyTemplateParameterList = false;
3137
3138 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
3139 if (SawNonEmptyTemplateParameterList) {
3140 if (!SuppressDiagnostic)
3141 Diag(DeclLoc, diag::err_specialize_member_of_template)
3142 << !Recovery << Range;
3143 Invalid = true;
3144 IsMemberSpecialization = false;
3145 return true;
3146 }
3147
3148 return false;
3149 };
3150
3151 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
3152 // Check that we can have an explicit specialization here.
3153 if (CheckExplicitSpecialization(Range, true))
3154 return true;
3155
3156 // We don't have a template header, but we should.
3157 SourceLocation ExpectedTemplateLoc;
3158 if (!ParamLists.empty())
3159 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
3160 else
3161 ExpectedTemplateLoc = DeclStartLoc;
3162
3163 if (!SuppressDiagnostic)
3164 Diag(DeclLoc, diag::err_template_spec_needs_header)
3165 << Range
3166 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
3167 return false;
3168 };
3169
3170 unsigned ParamIdx = 0;
3171 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
3172 ++TypeIdx) {
3173 T = NestedTypes[TypeIdx];
3174
3175 // Whether we expect a 'template<>' header.
3176 bool NeedEmptyTemplateHeader = false;
3177
3178 // Whether we expect a template header with parameters.
3179 bool NeedNonemptyTemplateHeader = false;
3180
3181 // For a dependent type, the set of template parameters that we
3182 // expect to see.
3183 TemplateParameterList *ExpectedTemplateParams = nullptr;
3184
3185 // C++0x [temp.expl.spec]p15:
3186 // A member or a member template may be nested within many enclosing
3187 // class templates. In an explicit specialization for such a member, the
3188 // member declaration shall be preceded by a template<> for each
3189 // enclosing class template that is explicitly specialized.
3190 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
3191 if (ClassTemplatePartialSpecializationDecl *Partial
3192 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
3193 ExpectedTemplateParams = Partial->getTemplateParameters();
3194 NeedNonemptyTemplateHeader = true;
3195 } else if (Record->isDependentType()) {
3196 if (Record->getDescribedClassTemplate()) {
3197 ExpectedTemplateParams = Record->getDescribedClassTemplate()
3198 ->getTemplateParameters();
3199 NeedNonemptyTemplateHeader = true;
3200 }
3201 } else if (ClassTemplateSpecializationDecl *Spec
3202 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
3203 // C++0x [temp.expl.spec]p4:
3204 // Members of an explicitly specialized class template are defined
3205 // in the same manner as members of normal classes, and not using
3206 // the template<> syntax.
3207 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
3208 NeedEmptyTemplateHeader = true;
3209 else
3210 continue;
3211 } else if (Record->getTemplateSpecializationKind()) {
3212 if (Record->getTemplateSpecializationKind()
3213 != TSK_ExplicitSpecialization &&
3214 TypeIdx == NumTypes - 1)
3215 IsMemberSpecialization = true;
3216
3217 continue;
3218 }
3219 } else if (const TemplateSpecializationType *TST
3220 = T->getAs<TemplateSpecializationType>()) {
3221 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
3222 ExpectedTemplateParams = Template->getTemplateParameters();
3223 NeedNonemptyTemplateHeader = true;
3224 }
3225 } else if (T->getAs<DependentTemplateSpecializationType>()) {
3226 // FIXME: We actually could/should check the template arguments here
3227 // against the corresponding template parameter list.
3228 NeedNonemptyTemplateHeader = false;
3229 }
3230
3231 // C++ [temp.expl.spec]p16:
3232 // In an explicit specialization declaration for a member of a class
3233 // template or a member template that ap- pears in namespace scope, the
3234 // member template and some of its enclosing class templates may remain
3235 // unspecialized, except that the declaration shall not explicitly
3236 // specialize a class member template if its en- closing class templates
3237 // are not explicitly specialized as well.
3238 if (ParamIdx < ParamLists.size()) {
3239 if (ParamLists[ParamIdx]->size() == 0) {
3240 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3241 false))
3242 return nullptr;
3243 } else
3244 SawNonEmptyTemplateParameterList = true;
3245 }
3246
3247 if (NeedEmptyTemplateHeader) {
3248 // If we're on the last of the types, and we need a 'template<>' header
3249 // here, then it's a member specialization.
3250 if (TypeIdx == NumTypes - 1)
3251 IsMemberSpecialization = true;
3252
3253 if (ParamIdx < ParamLists.size()) {
3254 if (ParamLists[ParamIdx]->size() > 0) {
3255 // The header has template parameters when it shouldn't. Complain.
3256 if (!SuppressDiagnostic)
3257 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3258 diag::err_template_param_list_matches_nontemplate)
3259 << T
3260 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
3261 ParamLists[ParamIdx]->getRAngleLoc())
3262 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3263 Invalid = true;
3264 return nullptr;
3265 }
3266
3267 // Consume this template header.
3268 ++ParamIdx;
3269 continue;
3270 }
3271
3272 if (!IsFriend)
3273 if (DiagnoseMissingExplicitSpecialization(
3274 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
3275 return nullptr;
3276
3277 continue;
3278 }
3279
3280 if (NeedNonemptyTemplateHeader) {
3281 // In friend declarations we can have template-ids which don't
3282 // depend on the corresponding template parameter lists. But
3283 // assume that empty parameter lists are supposed to match this
3284 // template-id.
3285 if (IsFriend && T->isDependentType()) {
3286 if (ParamIdx < ParamLists.size() &&
3287 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
3288 ExpectedTemplateParams = nullptr;
3289 else
3290 continue;
3291 }
3292
3293 if (ParamIdx < ParamLists.size()) {
3294 // Check the template parameter list, if we can.
3295 if (ExpectedTemplateParams &&
3296 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
3297 ExpectedTemplateParams,
3298 !SuppressDiagnostic, TPL_TemplateMatch))
3299 Invalid = true;
3300
3301 if (!Invalid &&
3302 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
3303 TPC_ClassTemplateMember))
3304 Invalid = true;
3305
3306 ++ParamIdx;
3307 continue;
3308 }
3309
3310 if (!SuppressDiagnostic)
3311 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
3312 << T
3313 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
3314 Invalid = true;
3315 continue;
3316 }
3317 }
3318
3319 // If there were at least as many template-ids as there were template
3320 // parameter lists, then there are no template parameter lists remaining for
3321 // the declaration itself.
3322 if (ParamIdx >= ParamLists.size()) {
3323 if (TemplateId && !IsFriend) {
3324 // We don't have a template header for the declaration itself, but we
3325 // should.
3326 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
3327 TemplateId->RAngleLoc));
3328
3329 // Fabricate an empty template parameter list for the invented header.
3330 return TemplateParameterList::Create(Context, SourceLocation(),
3331 SourceLocation(), None,
3332 SourceLocation(), nullptr);
3333 }
3334
3335 return nullptr;
3336 }
3337
3338 // If there were too many template parameter lists, complain about that now.
3339 if (ParamIdx < ParamLists.size() - 1) {
3340 bool HasAnyExplicitSpecHeader = false;
3341 bool AllExplicitSpecHeaders = true;
3342 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
3343 if (ParamLists[I]->size() == 0)
3344 HasAnyExplicitSpecHeader = true;
3345 else
3346 AllExplicitSpecHeaders = false;
3347 }
3348
3349 if (!SuppressDiagnostic)
3350 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
3351 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
3352 : diag::err_template_spec_extra_headers)
3353 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
3354 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
3355
3356 // If there was a specialization somewhere, such that 'template<>' is
3357 // not required, and there were any 'template<>' headers, note where the
3358 // specialization occurred.
3359 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader &&
3360 !SuppressDiagnostic)
3361 Diag(ExplicitSpecLoc,
3362 diag::note_explicit_template_spec_does_not_need_header)
3363 << NestedTypes.back();
3364
3365 // We have a template parameter list with no corresponding scope, which
3366 // means that the resulting template declaration can't be instantiated
3367 // properly (we'll end up with dependent nodes when we shouldn't).
3368 if (!AllExplicitSpecHeaders)
3369 Invalid = true;
3370 }
3371
3372 // C++ [temp.expl.spec]p16:
3373 // In an explicit specialization declaration for a member of a class
3374 // template or a member template that ap- pears in namespace scope, the
3375 // member template and some of its enclosing class templates may remain
3376 // unspecialized, except that the declaration shall not explicitly
3377 // specialize a class member template if its en- closing class templates
3378 // are not explicitly specialized as well.
3379 if (ParamLists.back()->size() == 0 &&
3380 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
3381 false))
3382 return nullptr;
3383
3384 // Return the last template parameter list, which corresponds to the
3385 // entity being declared.
3386 return ParamLists.back();
3387}
3388
3389void Sema::NoteAllFoundTemplates(TemplateName Name) {
3390 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
3391 Diag(Template->getLocation(), diag::note_template_declared_here)
3392 << (isa<FunctionTemplateDecl>(Template)
3393 ? 0
3394 : isa<ClassTemplateDecl>(Template)
3395 ? 1
3396 : isa<VarTemplateDecl>(Template)
3397 ? 2
3398 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
3399 << Template->getDeclName();
3400 return;
3401 }
3402
3403 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
3404 for (OverloadedTemplateStorage::iterator I = OST->begin(),
3405 IEnd = OST->end();
3406 I != IEnd; ++I)
3407 Diag((*I)->getLocation(), diag::note_template_declared_here)
3408 << 0 << (*I)->getDeclName();
3409
3410 return;
3411 }
3412}
3413
3414static QualType
3415checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
3416 const SmallVectorImpl<TemplateArgument> &Converted,
3417 SourceLocation TemplateLoc,
3418 TemplateArgumentListInfo &TemplateArgs) {
3419 ASTContext &Context = SemaRef.getASTContext();
3420 switch (BTD->getBuiltinTemplateKind()) {
3421 case BTK__make_integer_seq: {
3422 // Specializations of __make_integer_seq<S, T, N> are treated like
3423 // S<T, 0, ..., N-1>.
3424
3425 // C++14 [inteseq.intseq]p1:
3426 // T shall be an integer type.
3427 if (!Converted[1].getAsType()->isIntegralType(Context)) {
3428 SemaRef.Diag(TemplateArgs[1].getLocation(),
3429 diag::err_integer_sequence_integral_element_type);
3430 return QualType();
3431 }
3432
3433 // C++14 [inteseq.make]p1:
3434 // If N is negative the program is ill-formed.
3435 TemplateArgument NumArgsArg = Converted[2];
3436 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
3437 if (NumArgs < 0) {
3438 SemaRef.Diag(TemplateArgs[2].getLocation(),
3439 diag::err_integer_sequence_negative_length);
3440 return QualType();
3441 }
3442
3443 QualType ArgTy = NumArgsArg.getIntegralType();
3444 TemplateArgumentListInfo SyntheticTemplateArgs;
3445 // The type argument gets reused as the first template argument in the
3446 // synthetic template argument list.
3447 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
3448 // Expand N into 0 ... N-1.
3449 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3450 I < NumArgs; ++I) {
3451 TemplateArgument TA(Context, I, ArgTy);
3452 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3453 TA, ArgTy, TemplateArgs[2].getLocation()));
3454 }
3455 // The first template argument will be reused as the template decl that
3456 // our synthetic template arguments will be applied to.
3457 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3458 TemplateLoc, SyntheticTemplateArgs);
3459 }
3460
3461 case BTK__type_pack_element:
3462 // Specializations of
3463 // __type_pack_element<Index, T_1, ..., T_N>
3464 // are treated like T_Index.
3465 assert(Converted.size() == 2 &&
3466 "__type_pack_element should be given an index and a parameter pack");
3467
3468 // If the Index is out of bounds, the program is ill-formed.
3469 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3470 llvm::APSInt Index = IndexArg.getAsIntegral();
3471 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3472 "type std::size_t, and hence be non-negative");
3473 if (Index >= Ts.pack_size()) {
3474 SemaRef.Diag(TemplateArgs[0].getLocation(),
3475 diag::err_type_pack_element_out_of_bounds);
3476 return QualType();
3477 }
3478
3479 // We simply return the type at index `Index`.
3480 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
3481 return Nth->getAsType();
3482 }
3483 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3484}
3485
3486/// Determine whether this alias template is "enable_if_t".
3487static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3488 return AliasTemplate->getName().equals("enable_if_t");
3489}
3490
3491/// Collect all of the separable terms in the given condition, which
3492/// might be a conjunction.
3493///
3494/// FIXME: The right answer is to convert the logical expression into
3495/// disjunctive normal form, so we can find the first failed term
3496/// within each possible clause.
3497static void collectConjunctionTerms(Expr *Clause,
3498 SmallVectorImpl<Expr *> &Terms) {
3499 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3500 if (BinOp->getOpcode() == BO_LAnd) {
3501 collectConjunctionTerms(BinOp->getLHS(), Terms);
3502 collectConjunctionTerms(BinOp->getRHS(), Terms);
3503 }
3504
3505 return;
3506 }
3507
3508 Terms.push_back(Clause);
3509}
3510
3511// The ranges-v3 library uses an odd pattern of a top-level "||" with
3512// a left-hand side that is value-dependent but never true. Identify
3513// the idiom and ignore that term.
3514static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3515 // Top-level '||'.
3516 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3517 if (!BinOp) return Cond;
3518
3519 if (BinOp->getOpcode() != BO_LOr) return Cond;
3520
3521 // With an inner '==' that has a literal on the right-hand side.
3522 Expr *LHS = BinOp->getLHS();
3523 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3524 if (!InnerBinOp) return Cond;
3525
3526 if (InnerBinOp->getOpcode() != BO_EQ ||
3527 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3528 return Cond;
3529
3530 // If the inner binary operation came from a macro expansion named
3531 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3532 // of the '||', which is the real, user-provided condition.
3533 SourceLocation Loc = InnerBinOp->getExprLoc();
3534 if (!Loc.isMacroID()) return Cond;
3535
3536 StringRef MacroName = PP.getImmediateMacroName(Loc);
3537 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3538 return BinOp->getRHS();
3539
3540 return Cond;
3541}
3542
3543namespace {
3544
3545// A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3546// within failing boolean expression, such as substituting template parameters
3547// for actual types.
3548class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3549public:
3550 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3551 : Policy(P) {}
3552
3553 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3554 const auto *DR = dyn_cast<DeclRefExpr>(E);
3555 if (DR && DR->getQualifier()) {
3556 // If this is a qualified name, expand the template arguments in nested
3557 // qualifiers.
3558 DR->getQualifier()->print(OS, Policy, true);
3559 // Then print the decl itself.
3560 const ValueDecl *VD = DR->getDecl();
3561 OS << VD->getName();
3562 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3563 // This is a template variable, print the expanded template arguments.
3564 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3565 }
3566 return true;
3567 }
3568 return false;
3569 }
3570
3571private:
3572 const PrintingPolicy Policy;
3573};
3574
3575} // end anonymous namespace
3576
3577std::pair<Expr *, std::string>
3578Sema::findFailedBooleanCondition(Expr *Cond) {
3579 Cond = lookThroughRangesV3Condition(PP, Cond);
3580
3581 // Separate out all of the terms in a conjunction.
3582 SmallVector<Expr *, 4> Terms;
3583 collectConjunctionTerms(Cond, Terms);
3584
3585 // Determine which term failed.
3586 Expr *FailedCond = nullptr;
3587 for (Expr *Term : Terms) {
3588 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3589
3590 // Literals are uninteresting.
3591 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3592 isa<IntegerLiteral>(TermAsWritten))
3593 continue;
3594
3595 // The initialization of the parameter from the argument is
3596 // a constant-evaluated context.
3597 EnterExpressionEvaluationContext ConstantEvaluated(
3598 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3599
3600 bool Succeeded;
3601 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3602 !Succeeded) {
3603 FailedCond = TermAsWritten;
3604 break;
3605 }
3606 }
3607 if (!FailedCond)
3608 FailedCond = Cond->IgnoreParenImpCasts();
3609
3610 std::string Description;
3611 {
3612 llvm::raw_string_ostream Out(Description);
3613 PrintingPolicy Policy = getPrintingPolicy();
3614 Policy.PrintCanonicalTypes = true;
3615 FailedBooleanConditionPrinterHelper Helper(Policy);
3616 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3617 }
3618 return { FailedCond, Description };
3619}
3620
3621QualType Sema::CheckTemplateIdType(TemplateName Name,
3622 SourceLocation TemplateLoc,
3623 TemplateArgumentListInfo &TemplateArgs) {
3624 DependentTemplateName *DTN
3625 = Name.getUnderlying().getAsDependentTemplateName();
3626 if (DTN && DTN->isIdentifier())
3627 // When building a template-id where the template-name is dependent,
3628 // assume the template is a type template. Either our assumption is
3629 // correct, or the code is ill-formed and will be diagnosed when the
3630 // dependent name is substituted.
3631 return Context.getDependentTemplateSpecializationType(ETK_None,
3632 DTN->getQualifier(),
3633 DTN->getIdentifier(),
3634 TemplateArgs);
3635
3636 if (Name.getAsAssumedTemplateName() &&
3637 resolveAssumedTemplateNameAsType(/*Scope*/nullptr, Name, TemplateLoc))
3638 return QualType();
3639
3640 TemplateDecl *Template = Name.getAsTemplateDecl();
3641 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3642 isa<VarTemplateDecl>(Template) || isa<ConceptDecl>(Template)) {
3643 // We might have a substituted template template parameter pack. If so,
3644 // build a template specialization type for it.
3645 if (Name.getAsSubstTemplateTemplateParmPack())
3646 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3647
3648 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3649 << Name;
3650 NoteAllFoundTemplates(Name);
3651 return QualType();
3652 }
3653
3654 // Check that the template argument list is well-formed for this
3655 // template.
3656 SmallVector<TemplateArgument, 4> Converted;
3657 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3658 false, Converted,
3659 /*UpdateArgsWithConversion=*/true))
3660 return QualType();
3661
3662 QualType CanonType;
3663
3664 if (TypeAliasTemplateDecl *AliasTemplate =
3665 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3666
3667 // Find the canonical type for this type alias template specialization.
3668 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3669 if (Pattern->isInvalidDecl())
3670 return QualType();
3671
3672 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3673 Converted);
3674
3675 // Only substitute for the innermost template argument list.
3676 MultiLevelTemplateArgumentList TemplateArgLists;
3677 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3678 TemplateArgLists.addOuterRetainedLevels(
3679 AliasTemplate->getTemplateParameters()->getDepth());
3680
3681 LocalInstantiationScope Scope(*this);
3682 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3683 if (Inst.isInvalid())
3684 return QualType();
3685
3686 CanonType = SubstType(Pattern->getUnderlyingType(),
3687 TemplateArgLists, AliasTemplate->getLocation(),
3688 AliasTemplate->getDeclName());
3689 if (CanonType.isNull()) {
3690 // If this was enable_if and we failed to find the nested type
3691 // within enable_if in a SFINAE context, dig out the specific
3692 // enable_if condition that failed and present that instead.
3693 if (isEnableIfAliasTemplate(AliasTemplate)) {
3694 if (auto DeductionInfo = isSFINAEContext()) {
3695 if (*DeductionInfo &&
3696 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3697 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3698 diag::err_typename_nested_not_found_enable_if &&
3699 TemplateArgs[0].getArgument().getKind()
3700 == TemplateArgument::Expression) {
3701 Expr *FailedCond;
3702 std::string FailedDescription;
3703 std::tie(FailedCond, FailedDescription) =
3704 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3705
3706 // Remove the old SFINAE diagnostic.
3707 PartialDiagnosticAt OldDiag =
3708 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3709 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3710
3711 // Add a new SFINAE diagnostic specifying which condition
3712 // failed.
3713 (*DeductionInfo)->addSFINAEDiagnostic(
3714 OldDiag.first,
3715 PDiag(diag::err_typename_nested_not_found_requirement)
3716 << FailedDescription
3717 << FailedCond->getSourceRange());
3718 }
3719 }
3720 }
3721
3722 return QualType();
3723 }
3724 } else if (Name.isDependent() ||
3725 TemplateSpecializationType::anyDependentTemplateArguments(
3726 TemplateArgs, Converted)) {
3727 // This class template specialization is a dependent
3728 // type. Therefore, its canonical type is another class template
3729 // specialization type that contains all of the converted
3730 // arguments in canonical form. This ensures that, e.g., A<T> and
3731 // A<T, T> have identical types when A is declared as:
3732 //
3733 // template<typename T, typename U = T> struct A;
3734 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3735
3736 // This might work out to be a current instantiation, in which
3737 // case the canonical type needs to be the InjectedClassNameType.
3738 //
3739 // TODO: in theory this could be a simple hashtable lookup; most
3740 // changes to CurContext don't change the set of current
3741 // instantiations.
3742 if (isa<ClassTemplateDecl>(Template)) {
3743 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3744 // If we get out to a namespace, we're done.
3745 if (Ctx->isFileContext()) break;
3746
3747 // If this isn't a record, keep looking.
3748 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3749 if (!Record) continue;
3750
3751 // Look for one of the two cases with InjectedClassNameTypes
3752 // and check whether it's the same template.
3753 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3754 !Record->getDescribedClassTemplate())
3755 continue;
3756
3757 // Fetch the injected class name type and check whether its
3758 // injected type is equal to the type we just built.
3759 QualType ICNT = Context.getTypeDeclType(Record);
3760 QualType Injected = cast<InjectedClassNameType>(ICNT)
3761 ->getInjectedSpecializationType();
3762
3763 if (CanonType != Injected->getCanonicalTypeInternal())
3764 continue;
3765
3766 // If so, the canonical type of this TST is the injected
3767 // class name type of the record we just found.
3768 assert(ICNT.isCanonical());
3769 CanonType = ICNT;
3770 break;
3771 }
3772 }
3773 } else if (ClassTemplateDecl *ClassTemplate
3774 = dyn_cast<ClassTemplateDecl>(Template)) {
3775 // Find the class template specialization declaration that
3776 // corresponds to these arguments.
3777 void *InsertPos = nullptr;
3778 ClassTemplateSpecializationDecl *Decl
3779 = ClassTemplate->findSpecialization(Converted, InsertPos);
3780 if (!Decl) {
3781 // This is the first time we have referenced this class template
3782 // specialization. Create the canonical declaration and add it to
3783 // the set of specializations.
3784 Decl = ClassTemplateSpecializationDecl::Create(
3785 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3786 ClassTemplate->getDeclContext(),
3787 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3788 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3789 ClassTemplate->AddSpecialization(Decl, InsertPos);
3790 if (ClassTemplate->isOutOfLine())
3791 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3792 }
3793
3794 if (Decl->getSpecializationKind() == TSK_Undeclared &&
3795 ClassTemplate->getTemplatedDecl()->hasAttrs()) {
3796 InstantiatingTemplate Inst(*this, TemplateLoc, Decl);
3797 if (!Inst.isInvalid()) {
3798 MultiLevelTemplateArgumentList TemplateArgLists;
3799 TemplateArgLists.addOuterTemplateArguments(Converted);
3800 InstantiateAttrsForDecl(TemplateArgLists,
3801 ClassTemplate->getTemplatedDecl(), Decl);
3802 }
3803 }
3804
3805 // Diagnose uses of this specialization.
3806 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3807
3808 CanonType = Context.getTypeDeclType(Decl);
3809 assert(isa<RecordType>(CanonType) &&
3810 "type of non-dependent specialization is not a RecordType");
3811 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3812 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3813 TemplateArgs);
3814 }
3815
3816 // Build the fully-sugared type for this class template
3817 // specialization, which refers back to the class template
3818 // specialization we created or found.
3819 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3820}
3821
3822void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
3823 TemplateNameKind &TNK,
3824 SourceLocation NameLoc,
3825 IdentifierInfo *&II) {
3826 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
3827
3828 TemplateName Name = ParsedName.get();
3829 auto *ATN = Name.getAsAssumedTemplateName();
3830 assert(ATN && "not an assumed template name");
3831 II = ATN->getDeclName().getAsIdentifierInfo();
3832
3833 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
3834 // Resolved to a type template name.
3835 ParsedName = TemplateTy::make(Name);
3836 TNK = TNK_Type_template;
3837 }
3838}
3839
3840bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
3841 SourceLocation NameLoc,
3842 bool Diagnose) {
3843 // We assumed this undeclared identifier to be an (ADL-only) function
3844 // template name, but it was used in a context where a type was required.
3845 // Try to typo-correct it now.
3846 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
3847 assert(ATN && "not an assumed template name");
3848
3849 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
3850 struct CandidateCallback : CorrectionCandidateCallback {
3851 bool ValidateCandidate(const TypoCorrection &TC) override {
3852 return TC.getCorrectionDecl() &&
3853 getAsTypeTemplateDecl(TC.getCorrectionDecl());
3854 }
3855 std::unique_ptr<CorrectionCandidateCallback> clone() override {
3856 return std::make_unique<CandidateCallback>(*this);
3857 }
3858 } FilterCCC;
3859
3860 TypoCorrection Corrected =
3861 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
3862 FilterCCC, CTK_ErrorRecovery);
3863 if (Corrected && Corrected.getFoundDecl()) {
3864 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
3865 << ATN->getDeclName());
3866 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
3867 return false;
3868 }
3869
3870 if (Diagnose)
3871 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
3872 return true;
3873}
3874
3875TypeResult Sema::ActOnTemplateIdType(
3876 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3877 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3878 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
3879 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
3880 bool IsCtorOrDtorName, bool IsClassName) {
3881 if (SS.isInvalid())
3882 return true;
3883
3884 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3885 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3886
3887 // C++ [temp.res]p3:
3888 // A qualified-id that refers to a type and in which the
3889 // nested-name-specifier depends on a template-parameter (14.6.2)
3890 // shall be prefixed by the keyword typename to indicate that the
3891 // qualified-id denotes a type, forming an
3892 // elaborated-type-specifier (7.1.5.3).
3893 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3894 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3895 << SS.getScopeRep() << TemplateII->getName();
3896 // Recover as if 'typename' were specified.
3897 // FIXME: This is not quite correct recovery as we don't transform SS
3898 // into the corresponding dependent form (and we don't diagnose missing
3899 // 'template' keywords within SS as a result).
3900 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3901 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3902 TemplateArgsIn, RAngleLoc);
3903 }
3904
3905 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3906 // it's not actually allowed to be used as a type in most cases. Because
3907 // we annotate it before we know whether it's valid, we have to check for
3908 // this case here.
3909 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3910 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3911 Diag(TemplateIILoc,
3912 TemplateKWLoc.isInvalid()
3913 ? diag::err_out_of_line_qualified_id_type_names_constructor
3914 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3915 << TemplateII << 0 /*injected-class-name used as template name*/
3916 << 1 /*if any keyword was present, it was 'template'*/;
3917 }
3918 }
3919
3920 TemplateName Template = TemplateD.get();
3921 if (Template.getAsAssumedTemplateName() &&
3922 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
3923 return true;
3924
3925 // Translate the parser's template argument list in our AST format.
3926 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3927 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3928
3929 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3930 QualType T
3931 = Context.getDependentTemplateSpecializationType(ETK_None,
3932 DTN->getQualifier(),
3933 DTN->getIdentifier(),
3934 TemplateArgs);
3935 // Build type-source information.
3936 TypeLocBuilder TLB;
3937 DependentTemplateSpecializationTypeLoc SpecTL
3938 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3939 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3940 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3941 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3942 SpecTL.setTemplateNameLoc(TemplateIILoc);
3943 SpecTL.setLAngleLoc(LAngleLoc);
3944 SpecTL.setRAngleLoc(RAngleLoc);
3945 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3946 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3947 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3948 }
3949
3950 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3951 if (Result.isNull())
3952 return true;
3953
3954 // Build type-source information.
3955 TypeLocBuilder TLB;
3956 TemplateSpecializationTypeLoc SpecTL
3957 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3958 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3959 SpecTL.setTemplateNameLoc(TemplateIILoc);
3960 SpecTL.setLAngleLoc(LAngleLoc);
3961 SpecTL.setRAngleLoc(RAngleLoc);
3962 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3963 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3964
3965 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3966 // constructor or destructor name (in such a case, the scope specifier
3967 // will be attached to the enclosing Decl or Expr node).
3968 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3969 // Create an elaborated-type-specifier containing the nested-name-specifier.
3970 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3971 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3972 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3973 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3974 }
3975
3976 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3977}
3978
3979TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3980 TypeSpecifierType TagSpec,
3981 SourceLocation TagLoc,
3982 CXXScopeSpec &SS,
3983 SourceLocation TemplateKWLoc,
3984 TemplateTy TemplateD,
3985 SourceLocation TemplateLoc,
3986 SourceLocation LAngleLoc,
3987 ASTTemplateArgsPtr TemplateArgsIn,
3988 SourceLocation RAngleLoc) {
3989 if (SS.isInvalid())
3990 return TypeResult(true);
3991
3992 TemplateName Template = TemplateD.get();
3993
3994 // Translate the parser's template argument list in our AST format.
3995 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3996 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3997
3998 // Determine the tag kind
3999 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
4000 ElaboratedTypeKeyword Keyword
4001 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
4002
4003 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
4004 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
4005 DTN->getQualifier(),
4006 DTN->getIdentifier(),
4007 TemplateArgs);
4008
4009 // Build type-source information.
4010 TypeLocBuilder TLB;
4011 DependentTemplateSpecializationTypeLoc SpecTL
4012 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
4013 SpecTL.setElaboratedKeywordLoc(TagLoc);
4014 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
4015 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4016 SpecTL.setTemplateNameLoc(TemplateLoc);
4017 SpecTL.setLAngleLoc(LAngleLoc);
4018 SpecTL.setRAngleLoc(RAngleLoc);
4019 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
4020 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
4021 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
4022 }
4023
4024 if (TypeAliasTemplateDecl *TAT =
4025 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
4026 // C++0x [dcl.type.elab]p2:
4027 // If the identifier resolves to a typedef-name or the simple-template-id
4028 // resolves to an alias template specialization, the
4029 // elaborated-type-specifier is ill-formed.
4030 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
4031 << TAT << NTK_TypeAliasTemplate << TagKind;
4032 Diag(TAT->getLocation(), diag::note_declared_at);
4033 }
4034
4035 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
4036 if (Result.isNull())
4037 return TypeResult(true);
4038
4039 // Check the tag kind
4040 if (const RecordType *RT = Result->getAs<RecordType>()) {
4041 RecordDecl *D = RT->getDecl();
4042
4043 IdentifierInfo *Id = D->getIdentifier();
4044 assert(Id && "templated class must have an identifier");
4045
4046 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
4047 TagLoc, Id)) {
4048 Diag(TagLoc, diag::err_use_with_wrong_tag)
4049 << Result
4050 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
4051 Diag(D->getLocation(), diag::note_previous_use);
4052 }
4053 }
4054
4055 // Provide source-location information for the template specialization.
4056 TypeLocBuilder TLB;
4057 TemplateSpecializationTypeLoc SpecTL
4058 = TLB.push<TemplateSpecializationTypeLoc>(Result);
4059 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
4060 SpecTL.setTemplateNameLoc(TemplateLoc);
4061 SpecTL.setLAngleLoc(LAngleLoc);
4062 SpecTL.setRAngleLoc(RAngleLoc);
4063 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
4064 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
4065
4066 // Construct an elaborated type containing the nested-name-specifier (if any)
4067 // and tag keyword.
4068 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
4069 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
4070 ElabTL.setElaboratedKeywordLoc(TagLoc);
4071 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
4072 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
4073}
4074
4075static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
4076 NamedDecl *PrevDecl,
4077 SourceLocation Loc,
4078 bool IsPartialSpecialization);
4079
4080static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
4081
4082static bool isTemplateArgumentTemplateParameter(
4083 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
4084 switch (Arg.getKind()) {
4085 case TemplateArgument::Null:
4086 case TemplateArgument::NullPtr:
4087 case TemplateArgument::Integral:
4088 case TemplateArgument::Declaration:
4089 case TemplateArgument::Pack:
4090 case TemplateArgument::TemplateExpansion:
4091 return false;
4092
4093 case TemplateArgument::Type: {
4094 QualType Type = Arg.getAsType();
4095 const TemplateTypeParmType *TPT =
4096 Arg.getAsType()->getAs<TemplateTypeParmType>();
4097 return TPT && !Type.hasQualifiers() &&
4098 TPT->getDepth() == Depth && TPT->getIndex() == Index;
4099 }
4100
4101 case TemplateArgument::Expression: {
4102 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
4103 if (!DRE || !DRE->getDecl())
4104 return false;
4105 const NonTypeTemplateParmDecl *NTTP =
4106 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
4107 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
4108 }
4109
4110 case TemplateArgument::Template:
4111 const TemplateTemplateParmDecl *TTP =
4112 dyn_cast_or_null<TemplateTemplateParmDecl>(
4113 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
4114 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
4115 }
4116 llvm_unreachable("unexpected kind of template argument");
4117}
4118
4119static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
4120 ArrayRef<TemplateArgument> Args) {
4121 if (Params->size() != Args.size())
4122 return false;
4123
4124 unsigned Depth = Params->getDepth();
4125
4126 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
4127 TemplateArgument Arg = Args[I];
4128
4129 // If the parameter is a pack expansion, the argument must be a pack
4130 // whose only element is a pack expansion.
4131 if (Params->getParam(I)->isParameterPack()) {
4132 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
4133 !Arg.pack_begin()->isPackExpansion())
4134 return false;
4135 Arg = Arg.pack_begin()->getPackExpansionPattern();
4136 }
4137
4138 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
4139 return false;
4140 }
4141
4142 return true;
4143}
4144
4145template<typename PartialSpecDecl>
4146static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
4147 if (Partial->getDeclContext()->isDependentContext())
4148 return;
4149
4150 // FIXME: Get the TDK from deduction in order to provide better diagnostics
4151 // for non-substitution-failure issues?
4152 TemplateDeductionInfo Info(Partial->getLocation());
4153 if (S.isMoreSpecializedThanPrimary(Partial, Info))
4154 return;
4155
4156 auto *Template = Partial->getSpecializedTemplate();
4157 S.Diag(Partial->getLocation(),
4158 diag::ext_partial_spec_not_more_specialized_than_primary)
4159 << isa<VarTemplateDecl>(Template);
4160
4161 if (Info.hasSFINAEDiagnostic()) {
4162 PartialDiagnosticAt Diag = {SourceLocation(),
4163 PartialDiagnostic::NullDiagnostic()};
4164 Info.takeSFINAEDiagnostic(Diag);
4165 SmallString<128> SFINAEArgString;
4166 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
4167 S.Diag(Diag.first,
4168 diag::note_partial_spec_not_more_specialized_than_primary)
4169 << SFINAEArgString;
4170 }
4171
4172 S.Diag(Template->getLocation(), diag::note_template_decl_here);
4173 SmallVector<const Expr *, 3> PartialAC, TemplateAC;
4174 Template->getAssociatedConstraints(TemplateAC);
4175 Partial->getAssociatedConstraints(PartialAC);
4176 S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Partial, PartialAC, Template,
4177 TemplateAC);
4178}
4179
4180static void
4181noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
4182 const llvm::SmallBitVector &DeducibleParams) {
4183 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
4184 if (!DeducibleParams[I]) {
4185 NamedDecl *Param = TemplateParams->getParam(I);
4186 if (Param->getDeclName())
4187 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4188 << Param->getDeclName();
4189 else
4190 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
4191 << "(anonymous)";
4192 }
4193 }
4194}
4195
4196
4197template<typename PartialSpecDecl>
4198static void checkTemplatePartialSpecialization(Sema &S,
4199 PartialSpecDecl *Partial) {
4200 // C++1z [temp.class.spec]p8: (DR1495)
4201 // - The specialization shall be more specialized than the primary
4202 // template (14.5.5.2).
4203 checkMoreSpecializedThanPrimary(S, Partial);
4204
4205 // C++ [temp.class.spec]p8: (DR1315)
4206 // - Each template-parameter shall appear at least once in the
4207 // template-id outside a non-deduced context.
4208 // C++1z [temp.class.spec.match]p3 (P0127R2)
4209 // If the template arguments of a partial specialization cannot be
4210 // deduced because of the structure of its template-parameter-list
4211 // and the template-id, the program is ill-formed.
4212 auto *TemplateParams = Partial->getTemplateParameters();
4213 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4214 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
4215 TemplateParams->getDepth(), DeducibleParams);
4216
4217 if (!DeducibleParams.all()) {
4218 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4219 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
4220 << isa<VarTemplatePartialSpecializationDecl>(Partial)
4221 << (NumNonDeducible > 1)
4222 << SourceRange(Partial->getLocation(),
4223 Partial->getTemplateArgsAsWritten()->RAngleLoc);
4224 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
4225 }
4226}
4227
4228void Sema::CheckTemplatePartialSpecialization(
4229 ClassTemplatePartialSpecializationDecl *Partial) {
4230 checkTemplatePartialSpecialization(*this, Partial);
4231}
4232
4233void Sema::CheckTemplatePartialSpecialization(
4234 VarTemplatePartialSpecializationDecl *Partial) {
4235 checkTemplatePartialSpecialization(*this, Partial);
4236}
4237
4238void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
4239 // C++1z [temp.param]p11:
4240 // A template parameter of a deduction guide template that does not have a
4241 // default-argument shall be deducible from the parameter-type-list of the
4242 // deduction guide template.
4243 auto *TemplateParams = TD->getTemplateParameters();
4244 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
4245 MarkDeducedTemplateParameters(TD, DeducibleParams);
4246 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
4247 // A parameter pack is deducible (to an empty pack).
4248 auto *Param = TemplateParams->getParam(I);
4249 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
4250 DeducibleParams[I] = true;
4251 }
4252
4253 if (!DeducibleParams.all()) {
4254 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
4255 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
4256 << (NumNonDeducible > 1);
4257 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
4258 }
4259}
4260
4261DeclResult Sema::ActOnVarTemplateSpecialization(
4262 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
4263 TemplateParameterList *TemplateParams, StorageClass SC,
4264 bool IsPartialSpecialization) {
4265 // D must be variable template id.
4266 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
4267 "Variable template specialization is declared with a template it.");
4268
4269 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
4270 TemplateArgumentListInfo TemplateArgs =
4271 makeTemplateArgumentListInfo(*this, *TemplateId);
4272 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
4273 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
4274 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
4275
4276 TemplateName Name = TemplateId->Template.get();
4277
4278 // The template-id must name a variable template.
4279 VarTemplateDecl *VarTemplate =
4280 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
4281 if (!VarTemplate) {
4282 NamedDecl *FnTemplate;
4283 if (auto *OTS = Name.getAsOverloadedTemplate())
4284 FnTemplate = *OTS->begin();
4285 else
4286 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
4287 if (FnTemplate)
4288 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
4289 << FnTemplate->getDeclName();
4290 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
4291 << IsPartialSpecialization;
4292 }
4293
4294 // Check for unexpanded parameter packs in any of the template arguments.
4295 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
4296 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
4297 UPPC_PartialSpecialization))
4298 return true;
4299
4300 // Check that the template argument list is well-formed for this
4301 // template.
4302 SmallVector<TemplateArgument, 4> Converted;
4303 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
4304 false, Converted,
4305 /*UpdateArgsWithConversion=*/true))
4306 return true;
4307
4308 // Find the variable template (partial) specialization declaration that
4309 // corresponds to these arguments.
4310 if (IsPartialSpecialization) {
4311 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
4312 TemplateArgs.size(), Converted))
4313 return true;
4314
4315 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
4316 // also do them during instantiation.
4317 if (!Name.isDependent() &&
4318 !TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
4319 Converted)) {
4320 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
4321 << VarTemplate->getDeclName();
4322 IsPartialSpecialization = false;
4323 }
4324
4325 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
4326 Converted) &&
4327 (!Context.getLangOpts().CPlusPlus20 ||
4328 !TemplateParams->hasAssociatedConstraints())) {
4329 // C++ [temp.class.spec]p9b3:
4330 //
4331 // -- The argument list of the specialization shall not be identical
4332 // to the implicit argument list of the primary template.
4333 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
4334 << /*variable template*/ 1
4335 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
4336 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
4337 // FIXME: Recover from this by treating the declaration as a redeclaration
4338 // of the primary template.
4339 return true;
4340 }
4341 }
4342
4343 void *InsertPos = nullptr;
4344 VarTemplateSpecializationDecl *PrevDecl = nullptr;
4345
4346 if (IsPartialSpecialization)
4347 PrevDecl = VarTemplate->findPartialSpecialization(Converted, TemplateParams,
4348 InsertPos);
4349 else
4350 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
4351
4352 VarTemplateSpecializationDecl *Specialization = nullptr;
4353
4354 // Check whether we can declare a variable template specialization in
4355 // the current scope.
4356 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
4357 TemplateNameLoc,
4358 IsPartialSpecialization))
4359 return true;
4360
4361 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
4362 // Since the only prior variable template specialization with these
4363 // arguments was referenced but not declared, reuse that
4364 // declaration node as our own, updating its source location and
4365 // the list of outer template parameters to reflect our new declaration.
4366 Specialization = PrevDecl;
4367 Specialization->setLocation(TemplateNameLoc);
4368 PrevDecl = nullptr;
4369 } else if (IsPartialSpecialization) {
4370 // Create a new class template partial specialization declaration node.
4371 VarTemplatePartialSpecializationDecl *PrevPartial =
4372 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
4373 VarTemplatePartialSpecializationDecl *Partial =
4374 VarTemplatePartialSpecializationDecl::Create(
4375 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
4376 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
4377 Converted, TemplateArgs);
4378
4379 if (!PrevPartial)
4380 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
4381 Specialization = Partial;
4382
4383 // If we are providing an explicit specialization of a member variable
4384 // template specialization, make a note of that.
4385 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
4386 PrevPartial->setMemberSpecialization();
4387
4388 CheckTemplatePartialSpecialization(Partial);
4389 } else {
4390 // Create a new class template specialization declaration node for
4391 // this explicit specialization or friend declaration.
4392 Specialization = VarTemplateSpecializationDecl::Create(
4393 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
4394 VarTemplate, DI->getType(), DI, SC, Converted);
4395 Specialization->setTemplateArgsInfo(TemplateArgs);
4396
4397 if (!PrevDecl)
4398 VarTemplate->AddSpecialization(Specialization, InsertPos);
4399 }
4400
4401 // C++ [temp.expl.spec]p6:
4402 // If a template, a member template or the member of a class template is
4403 // explicitly specialized then that specialization shall be declared
4404 // before the first use of that specialization that would cause an implicit
4405 // instantiation to take place, in every translation unit in which such a
4406 // use occurs; no diagnostic is required.
4407 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
4408 bool Okay = false;
4409 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
4410 // Is there any previous explicit specialization declaration?
4411 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
4412 Okay = true;
4413 break;
4414 }
4415 }
4416
4417 if (!Okay) {
4418 SourceRange Range(TemplateNameLoc, RAngleLoc);
4419 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
4420 << Name << Range;
4421
4422 Diag(PrevDecl->getPointOfInstantiation(),
4423 diag::note_instantiation_required_here)
4424 << (PrevDecl->getTemplateSpecializationKind() !=
4425 TSK_ImplicitInstantiation);
4426 return true;
4427 }
4428 }
4429
4430 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4431 Specialization->setLexicalDeclContext(CurContext);
4432
4433 // Add the specialization into its lexical context, so that it can
4434 // be seen when iterating through the list of declarations in that
4435 // context. However, specializations are not found by name lookup.
4436 CurContext->addDecl(Specialization);
4437
4438 // Note that this is an explicit specialization.
4439 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4440
4441 if (PrevDecl) {
4442 // Check that this isn't a redefinition of this specialization,
4443 // merging with previous declarations.
4444 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4445 forRedeclarationInCurContext());
4446 PrevSpec.addDecl(PrevDecl);
4447 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4448 } else if (Specialization->isStaticDataMember() &&
4449 Specialization->isOutOfLine()) {
4450 Specialization->setAccess(VarTemplate->getAccess());
4451 }
4452
4453 return Specialization;
4454}
4455
4456namespace {
4457/// A partial specialization whose template arguments have matched
4458/// a given template-id.
4459struct PartialSpecMatchResult {
4460 VarTemplatePartialSpecializationDecl *Partial;
4461 TemplateArgumentList *Args;
4462};
4463} // end anonymous namespace
4464
4465DeclResult
4466Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4467 SourceLocation TemplateNameLoc,
4468 const TemplateArgumentListInfo &TemplateArgs) {
4469 assert(Template && "A variable template id without template?");
4470
4471 // Check that the template argument list is well-formed for this template.
4472 SmallVector<TemplateArgument, 4> Converted;
4473 if (CheckTemplateArgumentList(
4474 Template, TemplateNameLoc,
4475 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4476 Converted, /*UpdateArgsWithConversion=*/true))
4477 return true;
4478
4479 // Produce a placeholder value if the specialization is dependent.
4480 if (Template->getDeclContext()->isDependentContext() ||
4481 TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
4482 Converted))
4483 return DeclResult();
4484
4485 // Find the variable template specialization declaration that
4486 // corresponds to these arguments.
4487 void *InsertPos = nullptr;
4488 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4489 Converted, InsertPos)) {
4490 checkSpecializationVisibility(TemplateNameLoc, Spec);
4491 // If we already have a variable template specialization, return it.
4492 return Spec;
4493 }
4494
4495 // This is the first time we have referenced this variable template
4496 // specialization. Create the canonical declaration and add it to
4497 // the set of specializations, based on the closest partial specialization
4498 // that it represents. That is,
4499 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4500 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4501 Converted);
4502 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4503 bool AmbiguousPartialSpec = false;
4504 typedef PartialSpecMatchResult MatchResult;
4505 SmallVector<MatchResult, 4> Matched;
4506 SourceLocation PointOfInstantiation = TemplateNameLoc;
4507 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4508 /*ForTakingAddress=*/false);
4509
4510 // 1. Attempt to find the closest partial specialization that this
4511 // specializes, if any.
4512 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4513 // Perhaps better after unification of DeduceTemplateArguments() and
4514 // getMoreSpecializedPartialSpecialization().
4515 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4516 Template->getPartialSpecializations(PartialSpecs);
4517
4518 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4519 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4520 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4521
4522 if (TemplateDeductionResult Result =
4523 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4524 // Store the failed-deduction information for use in diagnostics, later.
4525 // TODO: Actually use the failed-deduction info?
4526 FailedCandidates.addCandidate().set(
4527 DeclAccessPair::make(Template, AS_public), Partial,
4528 MakeDeductionFailureInfo(Context, Result, Info));
4529 (void)Result;
4530 } else {
4531 Matched.push_back(PartialSpecMatchResult());
4532 Matched.back().Partial = Partial;
4533 Matched.back().Args = Info.take();
4534 }
4535 }
4536
4537 if (Matched.size() >= 1) {
4538 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4539 if (Matched.size() == 1) {
4540 // -- If exactly one matching specialization is found, the
4541 // instantiation is generated from that specialization.
4542 // We don't need to do anything for this.
4543 } else {
4544 // -- If more than one matching specialization is found, the
4545 // partial order rules (14.5.4.2) are used to determine
4546 // whether one of the specializations is more specialized
4547 // than the others. If none of the specializations is more
4548 // specialized than all of the other matching
4549 // specializations, then the use of the variable template is
4550 // ambiguous and the program is ill-formed.
4551 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4552 PEnd = Matched.end();
4553 P != PEnd; ++P) {
4554 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4555 PointOfInstantiation) ==
4556 P->Partial)
4557 Best = P;
4558 }
4559
4560 // Determine if the best partial specialization is more specialized than
4561 // the others.
4562 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4563 PEnd = Matched.end();
4564 P != PEnd; ++P) {
4565 if (P != Best && getMoreSpecializedPartialSpecialization(
4566 P->Partial, Best->Partial,
4567 PointOfInstantiation) != Best->Partial) {
4568 AmbiguousPartialSpec = true;
4569 break;
4570 }
4571 }
4572 }
4573
4574 // Instantiate using the best variable template partial specialization.
4575 InstantiationPattern = Best->Partial;
4576 InstantiationArgs = Best->Args;
4577 } else {
4578 // -- If no match is found, the instantiation is generated
4579 // from the primary template.
4580 // InstantiationPattern = Template->getTemplatedDecl();
4581 }
4582
4583 // 2. Create the canonical declaration.
4584 // Note that we do not instantiate a definition until we see an odr-use
4585 // in DoMarkVarDeclReferenced().
4586 // FIXME: LateAttrs et al.?
4587 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4588 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4589 Converted, TemplateNameLoc /*, LateAttrs, StartingScope*/);
4590 if (!Decl)
4591 return true;
4592
4593 if (AmbiguousPartialSpec) {
4594 // Partial ordering did not produce a clear winner. Complain.
4595 Decl->setInvalidDecl();
4596 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4597 << Decl;
4598
4599 // Print the matching partial specializations.
4600 for (MatchResult P : Matched)
4601 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4602 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4603 *P.Args);
4604 return true;
4605 }
4606
4607 if (VarTemplatePartialSpecializationDecl *D =
4608 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4609 Decl->setInstantiationOf(D, InstantiationArgs);
4610
4611 checkSpecializationVisibility(TemplateNameLoc, Decl);
4612
4613 assert(Decl && "No variable template specialization?");
4614 return Decl;
4615}
4616
4617ExprResult
4618Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4619 const DeclarationNameInfo &NameInfo,
4620 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4621 const TemplateArgumentListInfo *TemplateArgs) {
4622
4623 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4624 *TemplateArgs);
4625 if (Decl.isInvalid())
4626 return ExprError();
4627
4628 if (!Decl.get())
4629 return ExprResult();
4630
4631 VarDecl *Var = cast<VarDecl>(Decl.get());
4632 if (!Var->getTemplateSpecializationKind())
4633 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4634 NameInfo.getLoc());
4635
4636 // Build an ordinary singleton decl ref.
4637 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4638 /*FoundD=*/nullptr, TemplateArgs);
4639}
4640
4641void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4642 SourceLocation Loc) {
4643 Diag(Loc, diag::err_template_missing_args)
4644 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4645 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4646 Diag(TD->getLocation(), diag::note_template_decl_here)
4647 << TD->getTemplateParameters()->getSourceRange();
4648 }
4649}
4650
4651ExprResult
4652Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4653 SourceLocation TemplateKWLoc,
4654 const DeclarationNameInfo &ConceptNameInfo,
4655 NamedDecl *FoundDecl,
4656 ConceptDecl *NamedConcept,
4657 const TemplateArgumentListInfo *TemplateArgs) {
4658 assert(NamedConcept && "A concept template id without a template?");
4659
4660 llvm::SmallVector<TemplateArgument, 4> Converted;
4661 if (CheckTemplateArgumentList(NamedConcept, ConceptNameInfo.getLoc(),
4662 const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
4663 /*PartialTemplateArgs=*/false, Converted,
4664 /*UpdateArgsWithConversion=*/false))
4665 return ExprError();
4666
4667 ConstraintSatisfaction Satisfaction;
4668 bool AreArgsDependent =
4669 TemplateSpecializationType::anyDependentTemplateArguments(*TemplateArgs,
4670 Converted);
4671 if (!AreArgsDependent &&
4672 CheckConstraintSatisfaction(
4673 NamedConcept, {NamedConcept->getConstraintExpr()}, Converted,
4674 SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(),
4675 TemplateArgs->getRAngleLoc()),
4676 Satisfaction))
4677 return ExprError();
4678
4679 return ConceptSpecializationExpr::Create(Context,
4680 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
4681 TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,
4682 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
4683 AreArgsDependent ? nullptr : &Satisfaction);
4684}
4685
4686ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4687 SourceLocation TemplateKWLoc,
4688 LookupResult &R,
4689 bool RequiresADL,
4690 const TemplateArgumentListInfo *TemplateArgs) {
4691 // FIXME: Can we do any checking at this point? I guess we could check the
4692 // template arguments that we have against the template name, if the template
4693 // name refers to a single template. That's not a terribly common case,
4694 // though.
4695 // foo<int> could identify a single function unambiguously
4696 // This approach does NOT work, since f<int>(1);
4697 // gets resolved prior to resorting to overload resolution
4698 // i.e., template<class T> void f(double);
4699 // vs template<class T, class U> void f(U);
4700
4701 // These should be filtered out by our callers.
4702 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4703
4704 // Non-function templates require a template argument list.
4705 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4706 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4707 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4708 return ExprError();
4709 }
4710 }
4711
4712 // In C++1y, check variable template ids.
4713 if (R.getAsSingle<VarTemplateDecl>()) {
4714 ExprResult Res = CheckVarTemplateId(SS, R.getLookupNameInfo(),
4715 R.getAsSingle<VarTemplateDecl>(),
4716 TemplateKWLoc, TemplateArgs);
4717 if (Res.isInvalid() || Res.isUsable())
4718 return Res;
4719 // Result is dependent. Carry on to build an UnresolvedLookupEpxr.
4720 }
4721
4722 if (R.getAsSingle<ConceptDecl>()) {
4723 return CheckConceptTemplateId(SS, TemplateKWLoc, R.getLookupNameInfo(),
4724 R.getFoundDecl(),
4725 R.getAsSingle<ConceptDecl>(), TemplateArgs);
4726 }
4727
4728 // We don't want lookup warnings at this point.
4729 R.suppressDiagnostics();
4730
4731 UnresolvedLookupExpr *ULE
4732 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4733 SS.getWithLocInContext(Context),
4734 TemplateKWLoc,
4735 R.getLookupNameInfo(),
4736 RequiresADL, TemplateArgs,
4737 R.begin(), R.end());
4738
4739 return ULE;
4740}
4741
4742// We actually only call this from template instantiation.
4743ExprResult
4744Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4745 SourceLocation TemplateKWLoc,
4746 const DeclarationNameInfo &NameInfo,
4747 const TemplateArgumentListInfo *TemplateArgs) {
4748
4749 assert(TemplateArgs || TemplateKWLoc.isValid());
4750 DeclContext *DC;
4751 if (!(DC = computeDeclContext(SS, false)) ||
4752 DC->isDependentContext() ||
4753 RequireCompleteDeclContext(SS, DC))
4754 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4755
4756 bool MemberOfUnknownSpecialization;
4757 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4758 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4759 /*Entering*/false, MemberOfUnknownSpecialization,
4760 TemplateKWLoc))
4761 return ExprError();
4762
4763 if (R.isAmbiguous())
4764 return ExprError();
4765
4766 if (R.empty()) {
4767 Diag(NameInfo.getLoc(), diag::err_no_member)
4768 << NameInfo.getName() << DC << SS.getRange();
4769 return ExprError();
4770 }
4771
4772 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4773 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4774 << SS.getScopeRep()
4775 << NameInfo.getName().getAsString() << SS.getRange();
4776 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4777 return ExprError();
4778 }
4779
4780 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4781}
4782
4783/// Form a template name from a name that is syntactically required to name a
4784/// template, either due to use of the 'template' keyword or because a name in
4785/// this syntactic context is assumed to name a template (C++ [temp.names]p2-4).
4786///
4787/// This action forms a template name given the name of the template and its
4788/// optional scope specifier. This is used when the 'template' keyword is used
4789/// or when the parsing context unambiguously treats a following '<' as
4790/// introducing a template argument list. Note that this may produce a
4791/// non-dependent template name if we can perform the lookup now and identify
4792/// the named template.
4793///
4794/// For example, given "x.MetaFun::template apply", the scope specifier
4795/// \p SS will be "MetaFun::", \p TemplateKWLoc contains the location
4796/// of the "template" keyword, and "apply" is the \p Name.
4797TemplateNameKind Sema::ActOnTemplateName(Scope *S,
4798 CXXScopeSpec &SS,
4799 SourceLocation TemplateKWLoc,
4800 const UnqualifiedId &Name,
4801 ParsedType ObjectType,
4802 bool EnteringContext,
4803 TemplateTy &Result,
4804 bool AllowInjectedClassName) {
4805 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4806 Diag(TemplateKWLoc,
4807 getLangOpts().CPlusPlus11 ?
4808 diag::warn_cxx98_compat_template_outside_of_template :
4809 diag::ext_template_outside_of_template)
4810 << FixItHint::CreateRemoval(TemplateKWLoc);
4811
4812 if (SS.isInvalid())
4813 return TNK_Non_template;
4814
4815 // Figure out where isTemplateName is going to look.
4816 DeclContext *LookupCtx = nullptr;
4817 if (SS.isNotEmpty())
4818 LookupCtx = computeDeclContext(SS, EnteringContext);
4819 else if (ObjectType)
4820 LookupCtx = computeDeclContext(GetTypeFromParser(ObjectType));
4821
4822 // C++0x [temp.names]p5:
4823 // If a name prefixed by the keyword template is not the name of
4824 // a template, the program is ill-formed. [Note: the keyword
4825 // template may not be applied to non-template members of class
4826 // templates. -end note ] [ Note: as is the case with the
4827 // typename prefix, the template prefix is allowed in cases
4828 // where it is not strictly necessary; i.e., when the
4829 // nested-name-specifier or the expression on the left of the ->
4830 // or . is not dependent on a template-parameter, or the use
4831 // does not appear in the scope of a template. -end note]
4832 //
4833 // Note: C++03 was more strict here, because it banned the use of
4834 // the "template" keyword prior to a template-name that was not a
4835 // dependent name. C++ DR468 relaxed this requirement (the
4836 // "template" keyword is now permitted). We follow the C++0x
4837 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4838 bool MemberOfUnknownSpecialization;
4839 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4840 ObjectType, EnteringContext, Result,
4841 MemberOfUnknownSpecialization);
4842 if (TNK != TNK_Non_template) {
4843 // We resolved this to a (non-dependent) template name. Return it.
4844 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
4845 if (!AllowInjectedClassName && SS.isNotEmpty() && LookupRD &&
4846 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4847 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4848 // C++14 [class.qual]p2:
4849 // In a lookup in which function names are not ignored and the
4850 // nested-name-specifier nominates a class C, if the name specified
4851 // [...] is the injected-class-name of C, [...] the name is instead
4852 // considered to name the constructor
4853 //
4854 // We don't get here if naming the constructor would be valid, so we
4855 // just reject immediately and recover by treating the
4856 // injected-class-name as naming the template.
4857 Diag(Name.getBeginLoc(),
4858 diag::ext_out_of_line_qualified_id_type_names_constructor)
4859 << Name.Identifier
4860 << 0 /*injected-class-name used as template name*/
4861 << TemplateKWLoc.isValid();
4862 }
4863 return TNK;
4864 }
4865
4866 if (!MemberOfUnknownSpecialization) {
4867 // Didn't find a template name, and the lookup wasn't dependent.
4868 // Do the lookup again to determine if this is a "nothing found" case or
4869 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4870 // need to do this.
4871 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4872 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4873 LookupOrdinaryName);
4874 bool MOUS;
4875 // Tell LookupTemplateName that we require a template so that it diagnoses
4876 // cases where it finds a non-template.
4877 RequiredTemplateKind RTK = TemplateKWLoc.isValid()
4878 ? RequiredTemplateKind(TemplateKWLoc)
4879 : TemplateNameIsRequired;
4880 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext, MOUS,
4881 RTK, nullptr, /*AllowTypoCorrection=*/false) &&
4882 !R.isAmbiguous()) {
4883 if (LookupCtx)
4884 Diag(Name.getBeginLoc(), diag::err_no_member)
4885 << DNI.getName() << LookupCtx << SS.getRange();
4886 else
4887 Diag(Name.getBeginLoc(), diag::err_undeclared_use)
4888 << DNI.getName() << SS.getRange();
4889 }
4890 return TNK_Non_template;
4891 }
4892
4893 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4894
4895 switch (Name.getKind()) {
4896 case UnqualifiedIdKind::IK_Identifier:
4897 Result = TemplateTy::make(
4898 Context.getDependentTemplateName(Qualifier, Name.Identifier));
4899 return TNK_Dependent_template_name;
4900
4901 case UnqualifiedIdKind::IK_OperatorFunctionId:
4902 Result = TemplateTy::make(Context.getDependentTemplateName(
4903 Qualifier, Name.OperatorFunctionId.Operator));
4904 return TNK_Function_template;
4905
4906 case UnqualifiedIdKind::IK_LiteralOperatorId:
4907 // This is a kind of template name, but can never occur in a dependent
4908 // scope (literal operators can only be declared at namespace scope).
4909 break;
4910
4911 default:
4912 break;
4913 }
4914
4915 // This name cannot possibly name a dependent template. Diagnose this now
4916 // rather than building a dependent template name that can never be valid.
4917 Diag(Name.getBeginLoc(),
4918 diag::err_template_kw_refers_to_dependent_non_template)
4919 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4920 << TemplateKWLoc.isValid() << TemplateKWLoc;
4921 return TNK_Non_template;
4922}
4923
4924bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4925 TemplateArgumentLoc &AL,
4926 SmallVectorImpl<TemplateArgument> &Converted) {
4927 const TemplateArgument &Arg = AL.getArgument();
4928 QualType ArgType;
4929 TypeSourceInfo *TSI = nullptr;
4930
4931 // Check template type parameter.
4932 switch(Arg.getKind()) {
4933 case TemplateArgument::Type:
4934 // C++ [temp.arg.type]p1:
4935 // A template-argument for a template-parameter which is a
4936 // type shall be a type-id.
4937 ArgType = Arg.getAsType();
4938 TSI = AL.getTypeSourceInfo();
4939 break;
4940 case TemplateArgument::Template:
4941 case TemplateArgument::TemplateExpansion: {
4942 // We have a template type parameter but the template argument
4943 // is a template without any arguments.
4944 SourceRange SR = AL.getSourceRange();
4945 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4946 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4947 return true;
4948 }
4949 case TemplateArgument::Expression: {
4950 // We have a template type parameter but the template argument is an
4951 // expression; see if maybe it is missing the "typename" keyword.
4952 CXXScopeSpec SS;
4953 DeclarationNameInfo NameInfo;
4954
4955 if (DependentScopeDeclRefExpr *ArgExpr =
4956 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4957 SS.Adopt(ArgExpr->getQualifierLoc());
4958 NameInfo = ArgExpr->getNameInfo();
4959 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4960 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4961 if (ArgExpr->isImplicitAccess()) {
4962 SS.Adopt(ArgExpr->getQualifierLoc());
4963 NameInfo = ArgExpr->getMemberNameInfo();
4964 }
4965 }
4966
4967 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4968 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4969 LookupParsedName(Result, CurScope, &SS);
4970
4971 if (Result.getAsSingle<TypeDecl>() ||
4972 Result.getResultKind() ==
4973 LookupResult::NotFoundInCurrentInstantiation) {
4974 assert(SS.getScopeRep() && "dependent scope expr must has a scope!");
4975 // Suggest that the user add 'typename' before the NNS.
4976 SourceLocation Loc = AL.getSourceRange().getBegin();
4977 Diag(Loc, getLangOpts().MSVCCompat
4978 ? diag::ext_ms_template_type_arg_missing_typename
4979 : diag::err_template_arg_must_be_type_suggest)
4980 << FixItHint::CreateInsertion(Loc, "typename ");
4981 Diag(Param->getLocation(), diag::note_template_param_here);
4982
4983 // Recover by synthesizing a type using the location information that we
4984 // already have.
4985 ArgType =
4986 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4987 TypeLocBuilder TLB;
4988 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4989 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4990 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4991 TL.setNameLoc(NameInfo.getLoc());
4992 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4993
4994 // Overwrite our input TemplateArgumentLoc so that we can recover
4995 // properly.
4996 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4997 TemplateArgumentLocInfo(TSI));
4998
4999 break;
5000 }
5001 }
5002 // fallthrough
5003 LLVM_FALLTHROUGH;
5004 }
5005 default: {
5006 // We have a template type parameter but the template argument
5007 // is not a type.
5008 SourceRange SR = AL.getSourceRange();
5009 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
5010 Diag(Param->getLocation(), diag::note_template_param_here);
5011
5012 return true;
5013 }
5014 }
5015
5016 if (CheckTemplateArgument(Param, TSI))
5017 return true;
5018
5019 // Add the converted template type argument.
5020 ArgType = Context.getCanonicalType(ArgType);
5021
5022 // Objective-C ARC:
5023 // If an explicitly-specified template argument type is a lifetime type
5024 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
5025 if (getLangOpts().ObjCAutoRefCount &&
5026 ArgType->isObjCLifetimeType() &&
5027 !ArgType.getObjCLifetime()) {
5028 Qualifiers Qs;
5029 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
5030 ArgType = Context.getQualifiedType(ArgType, Qs);
5031 }
5032
5033 Converted.push_back(TemplateArgument(ArgType));
5034 return false;
5035}
5036
5037/// Substitute template arguments into the default template argument for
5038/// the given template type parameter.
5039///
5040/// \param SemaRef the semantic analysis object for which we are performing
5041/// the substitution.
5042///
5043/// \param Template the template that we are synthesizing template arguments
5044/// for.
5045///
5046/// \param TemplateLoc the location of the template name that started the
5047/// template-id we are checking.
5048///
5049/// \param RAngleLoc the location of the right angle bracket ('>') that
5050/// terminates the template-id.
5051///
5052/// \param Param the template template parameter whose default we are
5053/// substituting into.
5054///
5055/// \param Converted the list of template arguments provided for template
5056/// parameters that precede \p Param in the template parameter list.
5057/// \returns the substituted template argument, or NULL if an error occurred.
5058static TypeSourceInfo *
5059SubstDefaultTemplateArgument(Sema &SemaRef,
5060 TemplateDecl *Template,
5061 SourceLocation TemplateLoc,
5062 SourceLocation RAngleLoc,
5063 TemplateTypeParmDecl *Param,
5064 SmallVectorImpl<TemplateArgument> &Converted) {
5065 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
5066
5067 // If the argument type is dependent, instantiate it now based
5068 // on the previously-computed template arguments.
5069 if (ArgType->getType()->isInstantiationDependentType()) {
5070 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
5071 Param, Template, Converted,
5072 SourceRange(TemplateLoc, RAngleLoc));
5073 if (Inst.isInvalid())
5074 return nullptr;
5075
5076 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5077
5078 // Only substitute for the innermost template argument list.
5079 MultiLevelTemplateArgumentList TemplateArgLists;
5080 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
5081 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5082 TemplateArgLists.addOuterTemplateArguments(None);
5083
5084 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5085 ArgType =
5086 SemaRef.SubstType(ArgType, TemplateArgLists,
5087 Param->getDefaultArgumentLoc(), Param->getDeclName());
5088 }
5089
5090 return ArgType;
5091}
5092
5093/// Substitute template arguments into the default template argument for
5094/// the given non-type template parameter.
5095///
5096/// \param SemaRef the semantic analysis object for which we are performing
5097/// the substitution.
5098///
5099/// \param Template the template that we are synthesizing template arguments
5100/// for.
5101///
5102/// \param TemplateLoc the location of the template name that started the
5103/// template-id we are checking.
5104///
5105/// \param RAngleLoc the location of the right angle bracket ('>') that
5106/// terminates the template-id.
5107///
5108/// \param Param the non-type template parameter whose default we are
5109/// substituting into.
5110///
5111/// \param Converted the list of template arguments provided for template
5112/// parameters that precede \p Param in the template parameter list.
5113///
5114/// \returns the substituted template argument, or NULL if an error occurred.
5115static ExprResult
5116SubstDefaultTemplateArgument(Sema &SemaRef,
5117 TemplateDecl *Template,
5118 SourceLocation TemplateLoc,
5119 SourceLocation RAngleLoc,
5120 NonTypeTemplateParmDecl *Param,
5121 SmallVectorImpl<TemplateArgument> &Converted) {
5122 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
5123 Param, Template, Converted,
5124 SourceRange(TemplateLoc, RAngleLoc));
5125 if (Inst.isInvalid())
5126 return ExprError();
5127
5128 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5129
5130 // Only substitute for the innermost template argument list.
5131 MultiLevelTemplateArgumentList TemplateArgLists;
5132 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
5133 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5134 TemplateArgLists.addOuterTemplateArguments(None);
5135
5136 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5137 EnterExpressionEvaluationContext ConstantEvaluated(
5138 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
5139 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
5140}
5141
5142/// Substitute template arguments into the default template argument for
5143/// the given template template parameter.
5144///
5145/// \param SemaRef the semantic analysis object for which we are performing
5146/// the substitution.
5147///
5148/// \param Template the template that we are synthesizing template arguments
5149/// for.
5150///
5151/// \param TemplateLoc the location of the template name that started the
5152/// template-id we are checking.
5153///
5154/// \param RAngleLoc the location of the right angle bracket ('>') that
5155/// terminates the template-id.
5156///
5157/// \param Param the template template parameter whose default we are
5158/// substituting into.
5159///
5160/// \param Converted the list of template arguments provided for template
5161/// parameters that precede \p Param in the template parameter list.
5162///
5163/// \param QualifierLoc Will be set to the nested-name-specifier (with
5164/// source-location information) that precedes the template name.
5165///
5166/// \returns the substituted template argument, or NULL if an error occurred.
5167static TemplateName
5168SubstDefaultTemplateArgument(Sema &SemaRef,
5169 TemplateDecl *Template,
5170 SourceLocation TemplateLoc,
5171 SourceLocation RAngleLoc,
5172 TemplateTemplateParmDecl *Param,
5173 SmallVectorImpl<TemplateArgument> &Converted,
5174 NestedNameSpecifierLoc &QualifierLoc) {
5175 Sema::InstantiatingTemplate Inst(
5176 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
5177 SourceRange(TemplateLoc, RAngleLoc));
5178 if (Inst.isInvalid())
5179 return TemplateName();
5180
5181 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5182
5183 // Only substitute for the innermost template argument list.
5184 MultiLevelTemplateArgumentList TemplateArgLists;
5185 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
5186 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
5187 TemplateArgLists.addOuterTemplateArguments(None);
5188
5189 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
5190 // Substitute into the nested-name-specifier first,
5191 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
5192 if (QualifierLoc) {
5193 QualifierLoc =
5194 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
5195 if (!QualifierLoc)
5196 return TemplateName();
5197 }
5198
5199 return SemaRef.SubstTemplateName(
5200 QualifierLoc,
5201 Param->getDefaultArgument().getArgument().getAsTemplate(),
5202 Param->getDefaultArgument().getTemplateNameLoc(),
5203 TemplateArgLists);
5204}
5205
5206/// If the given template parameter has a default template
5207/// argument, substitute into that default template argument and
5208/// return the corresponding template argument.
5209TemplateArgumentLoc
5210Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
5211 SourceLocation TemplateLoc,
5212 SourceLocation RAngleLoc,
5213 Decl *Param,
5214 SmallVectorImpl<TemplateArgument>
5215 &Converted,
5216 bool &HasDefaultArg) {
5217 HasDefaultArg = false;
5218
5219 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
5220 if (!hasVisibleDefaultArgument(TypeParm))
5221 return TemplateArgumentLoc();
5222
5223 HasDefaultArg = true;
5224 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
5225 TemplateLoc,
5226 RAngleLoc,
5227 TypeParm,
5228 Converted);
5229 if (DI)
5230 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
5231
5232 return TemplateArgumentLoc();
5233 }
5234
5235 if (NonTypeTemplateParmDecl *NonTypeParm
5236 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5237 if (!hasVisibleDefaultArgument(NonTypeParm))
5238 return TemplateArgumentLoc();
5239
5240 HasDefaultArg = true;
5241 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
5242 TemplateLoc,
5243 RAngleLoc,
5244 NonTypeParm,
5245 Converted);
5246 if (Arg.isInvalid())
5247 return TemplateArgumentLoc();
5248
5249 Expr *ArgE = Arg.getAs<Expr>();
5250 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
5251 }
5252
5253 TemplateTemplateParmDecl *TempTempParm
5254 = cast<TemplateTemplateParmDecl>(Param);
5255 if (!hasVisibleDefaultArgument(TempTempParm))
5256 return TemplateArgumentLoc();
5257
5258 HasDefaultArg = true;
5259 NestedNameSpecifierLoc QualifierLoc;
5260 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
5261 TemplateLoc,
5262 RAngleLoc,
5263 TempTempParm,
5264 Converted,
5265 QualifierLoc);
5266 if (TName.isNull())
5267 return TemplateArgumentLoc();
5268
5269 return TemplateArgumentLoc(
5270 Context, TemplateArgument(TName),
5271 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
5272 TempTempParm->getDefaultArgument().getTemplateNameLoc());
5273}
5274
5275/// Convert a template-argument that we parsed as a type into a template, if
5276/// possible. C++ permits injected-class-names to perform dual service as
5277/// template template arguments and as template type arguments.
5278static TemplateArgumentLoc
5279convertTypeTemplateArgumentToTemplate(ASTContext &Context, TypeLoc TLoc) {
5280 // Extract and step over any surrounding nested-name-specifier.
5281 NestedNameSpecifierLoc QualLoc;
5282 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
5283 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
5284 return TemplateArgumentLoc();
5285
5286 QualLoc = ETLoc.getQualifierLoc();
5287 TLoc = ETLoc.getNamedTypeLoc();
5288 }
5289 // If this type was written as an injected-class-name, it can be used as a
5290 // template template argument.
5291 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
5292 return TemplateArgumentLoc(Context, InjLoc.getTypePtr()->getTemplateName(),
5293 QualLoc, InjLoc.getNameLoc());
5294
5295 // If this type was written as an injected-class-name, it may have been
5296 // converted to a RecordType during instantiation. If the RecordType is
5297 // *not* wrapped in a TemplateSpecializationType and denotes a class
5298 // template specialization, it must have come from an injected-class-name.
5299 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
5300 if (auto *CTSD =
5301 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
5302 return TemplateArgumentLoc(Context,
5303 TemplateName(CTSD->getSpecializedTemplate()),
5304 QualLoc, RecLoc.getNameLoc());
5305
5306 return TemplateArgumentLoc();
5307}
5308
5309/// Check that the given template argument corresponds to the given
5310/// template parameter.
5311///
5312/// \param Param The template parameter against which the argument will be
5313/// checked.
5314///
5315/// \param Arg The template argument, which may be updated due to conversions.
5316///
5317/// \param Template The template in which the template argument resides.
5318///
5319/// \param TemplateLoc The location of the template name for the template
5320/// whose argument list we're matching.
5321///
5322/// \param RAngleLoc The location of the right angle bracket ('>') that closes
5323/// the template argument list.
5324///
5325/// \param ArgumentPackIndex The index into the argument pack where this
5326/// argument will be placed. Only valid if the parameter is a parameter pack.
5327///
5328/// \param Converted The checked, converted argument will be added to the
5329/// end of this small vector.
5330///
5331/// \param CTAK Describes how we arrived at this particular template argument:
5332/// explicitly written, deduced, etc.
5333///
5334/// \returns true on error, false otherwise.
5335bool Sema::CheckTemplateArgument(NamedDecl *Param,
5336 TemplateArgumentLoc &Arg,
5337 NamedDecl *Template,
5338 SourceLocation TemplateLoc,
5339 SourceLocation RAngleLoc,
5340 unsigned ArgumentPackIndex,
5341 SmallVectorImpl<TemplateArgument> &Converted,
5342 CheckTemplateArgumentKind CTAK) {
5343 // Check template type parameters.
5344 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
5345 return CheckTemplateTypeArgument(TTP, Arg, Converted);
5346
5347 // Check non-type template parameters.
5348 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5349 // Do substitution on the type of the non-type template parameter
5350 // with the template arguments we've seen thus far. But if the
5351 // template has a dependent context then we cannot substitute yet.
5352 QualType NTTPType = NTTP->getType();
5353 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
5354 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
5355
5356 if (NTTPType->isInstantiationDependentType() &&
5357 !isa<TemplateTemplateParmDecl>(Template) &&
5358 !Template->getDeclContext()->isDependentContext()) {
5359 // Do substitution on the type of the non-type template parameter.
5360 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5361 NTTP, Converted,
5362 SourceRange(TemplateLoc, RAngleLoc));
5363 if (Inst.isInvalid())
5364 return true;
5365
5366 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
5367 Converted);
5368
5369 // If the parameter is a pack expansion, expand this slice of the pack.
5370 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
5371 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
5372 ArgumentPackIndex);
5373 NTTPType = SubstType(PET->getPattern(),
5374 MultiLevelTemplateArgumentList(TemplateArgs),
5375 NTTP->getLocation(),
5376 NTTP->getDeclName());
5377 } else {
5378 NTTPType = SubstType(NTTPType,
5379 MultiLevelTemplateArgumentList(TemplateArgs),
5380 NTTP->getLocation(),
5381 NTTP->getDeclName());
5382 }
5383
5384 // If that worked, check the non-type template parameter type
5385 // for validity.
5386 if (!NTTPType.isNull())
5387 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
5388 NTTP->getLocation());
5389 if (NTTPType.isNull())
5390 return true;
5391 }
5392
5393 switch (Arg.getArgument().getKind()) {
5394 case TemplateArgument::Null:
5395 llvm_unreachable("Should never see a NULL template argument here");
5396
5397 case TemplateArgument::Expression: {
5398 TemplateArgument Result;
5399 unsigned CurSFINAEErrors = NumSFINAEErrors;
5400 ExprResult Res =
5401 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
5402 Result, CTAK);
5403 if (Res.isInvalid())
5404 return true;
5405 // If the current template argument causes an error, give up now.
5406 if (CurSFINAEErrors < NumSFINAEErrors)
5407 return true;
5408
5409 // If the resulting expression is new, then use it in place of the
5410 // old expression in the template argument.
5411 if (Res.get() != Arg.getArgument().getAsExpr()) {
5412 TemplateArgument TA(Res.get());
5413 Arg = TemplateArgumentLoc(TA, Res.get());
5414 }
5415
5416 Converted.push_back(Result);
5417 break;
5418 }
5419
5420 case TemplateArgument::Declaration:
5421 case TemplateArgument::Integral:
5422 case TemplateArgument::NullPtr:
5423 // We've already checked this template argument, so just copy
5424 // it to the list of converted arguments.
5425 Converted.push_back(Arg.getArgument());
5426 break;
5427
5428 case TemplateArgument::Template:
5429 case TemplateArgument::TemplateExpansion:
5430 // We were given a template template argument. It may not be ill-formed;
5431 // see below.
5432 if (DependentTemplateName *DTN
5433 = Arg.getArgument().getAsTemplateOrTemplatePattern()
5434 .getAsDependentTemplateName()) {
5435 // We have a template argument such as \c T::template X, which we
5436 // parsed as a template template argument. However, since we now
5437 // know that we need a non-type template argument, convert this
5438 // template name into an expression.
5439
5440 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
5441 Arg.getTemplateNameLoc());
5442
5443 CXXScopeSpec SS;
5444 SS.Adopt(Arg.getTemplateQualifierLoc());
5445 // FIXME: the template-template arg was a DependentTemplateName,
5446 // so it was provided with a template keyword. However, its source
5447 // location is not stored in the template argument structure.
5448 SourceLocation TemplateKWLoc;
5449 ExprResult E = DependentScopeDeclRefExpr::Create(
5450 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5451 nullptr);
5452
5453 // If we parsed the template argument as a pack expansion, create a
5454 // pack expansion expression.
5455 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5456 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5457 if (E.isInvalid())
5458 return true;
5459 }
5460
5461 TemplateArgument Result;
5462 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5463 if (E.isInvalid())
5464 return true;
5465
5466 Converted.push_back(Result);
5467 break;
5468 }
5469
5470 // We have a template argument that actually does refer to a class
5471 // template, alias template, or template template parameter, and
5472 // therefore cannot be a non-type template argument.
5473 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5474 << Arg.getSourceRange();
5475
5476 Diag(Param->getLocation(), diag::note_template_param_here);
5477 return true;
5478
5479 case TemplateArgument::Type: {
5480 // We have a non-type template parameter but the template
5481 // argument is a type.
5482
5483 // C++ [temp.arg]p2:
5484 // In a template-argument, an ambiguity between a type-id and
5485 // an expression is resolved to a type-id, regardless of the
5486 // form of the corresponding template-parameter.
5487 //
5488 // We warn specifically about this case, since it can be rather
5489 // confusing for users.
5490 QualType T = Arg.getArgument().getAsType();
5491 SourceRange SR = Arg.getSourceRange();
5492 if (T->isFunctionType())
5493 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5494 else
5495 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5496 Diag(Param->getLocation(), diag::note_template_param_here);
5497 return true;
5498 }
5499
5500 case TemplateArgument::Pack:
5501 llvm_unreachable("Caller must expand template argument packs");
5502 }
5503
5504 return false;
5505 }
5506
5507
5508 // Check template template parameters.
5509 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5510
5511 TemplateParameterList *Params = TempParm->getTemplateParameters();
5512 if (TempParm->isExpandedParameterPack())
5513 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5514
5515 // Substitute into the template parameter list of the template
5516 // template parameter, since previously-supplied template arguments
5517 // may appear within the template template parameter.
5518 //
5519 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5520 {
5521 // Set up a template instantiation context.
5522 LocalInstantiationScope Scope(*this);
5523 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5524 TempParm, Converted,
5525 SourceRange(TemplateLoc, RAngleLoc));
5526 if (Inst.isInvalid())
5527 return true;
5528
5529 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5530 Params = SubstTemplateParams(Params, CurContext,
5531 MultiLevelTemplateArgumentList(TemplateArgs));
5532 if (!Params)
5533 return true;
5534 }
5535
5536 // C++1z [temp.local]p1: (DR1004)
5537 // When [the injected-class-name] is used [...] as a template-argument for
5538 // a template template-parameter [...] it refers to the class template
5539 // itself.
5540 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5541 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5542 Context, Arg.getTypeSourceInfo()->getTypeLoc());
5543 if (!ConvertedArg.getArgument().isNull())
5544 Arg = ConvertedArg;
5545 }
5546
5547 switch (Arg.getArgument().getKind()) {
5548 case TemplateArgument::Null:
5549 llvm_unreachable("Should never see a NULL template argument here");
5550
5551 case TemplateArgument::Template:
5552 case TemplateArgument::TemplateExpansion:
5553 if (CheckTemplateTemplateArgument(TempParm, Params, Arg))
5554 return true;
5555
5556 Converted.push_back(Arg.getArgument());
5557 break;
5558
5559 case TemplateArgument::Expression:
5560 case TemplateArgument::Type:
5561 // We have a template template parameter but the template
5562 // argument does not refer to a template.
5563 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5564 << getLangOpts().CPlusPlus11;
5565 return true;
5566
5567 case TemplateArgument::Declaration:
5568 llvm_unreachable("Declaration argument with template template parameter");
5569 case TemplateArgument::Integral:
5570 llvm_unreachable("Integral argument with template template parameter");
5571 case TemplateArgument::NullPtr:
5572 llvm_unreachable("Null pointer argument with template template parameter");
5573
5574 case TemplateArgument::Pack:
5575 llvm_unreachable("Caller must expand template argument packs");
5576 }
5577
5578 return false;
5579}
5580
5581/// Diagnose a missing template argument.
5582template<typename TemplateParmDecl>
5583static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5584 TemplateDecl *TD,
5585 const TemplateParmDecl *D,
5586 TemplateArgumentListInfo &Args) {
5587 // Dig out the most recent declaration of the template parameter; there may be
5588 // declarations of the template that are more recent than TD.
5589 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5590 ->getTemplateParameters()
5591 ->getParam(D->getIndex()));
5592
5593 // If there's a default argument that's not visible, diagnose that we're
5594 // missing a module import.
5595 llvm::SmallVector<Module*, 8> Modules;
5596 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5597 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5598 D->getDefaultArgumentLoc(), Modules,
5599 Sema::MissingImportKind::DefaultArgument,
5600 /*Recover*/true);
5601 return true;
5602 }
5603
5604 // FIXME: If there's a more recent default argument that *is* visible,
5605 // diagnose that it was declared too late.
5606
5607 TemplateParameterList *Params = TD->getTemplateParameters();
5608
5609 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5610 << /*not enough args*/0
5611 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5612 << TD;
5613 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5614 << Params->getSourceRange();
5615 return true;
5616}
5617
5618/// Check that the given template argument list is well-formed
5619/// for specializing the given template.
5620bool Sema::CheckTemplateArgumentList(
5621 TemplateDecl *Template, SourceLocation TemplateLoc,
5622 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5623 SmallVectorImpl<TemplateArgument> &Converted,
5624 bool UpdateArgsWithConversions, bool *ConstraintsNotSatisfied) {
5625
5626 if (ConstraintsNotSatisfied)
5627 *ConstraintsNotSatisfied = false;
5628
5629 // Make a copy of the template arguments for processing. Only make the
5630 // changes at the end when successful in matching the arguments to the
5631 // template.
5632 TemplateArgumentListInfo NewArgs = TemplateArgs;
5633
5634 // Make sure we get the template parameter list from the most
5635 // recentdeclaration, since that is the only one that has is guaranteed to
5636 // have all the default template argument information.
5637 TemplateParameterList *Params =
5638 cast<TemplateDecl>(Template->getMostRecentDecl())
5639 ->getTemplateParameters();
5640
5641 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5642
5643 // C++ [temp.arg]p1:
5644 // [...] The type and form of each template-argument specified in
5645 // a template-id shall match the type and form specified for the
5646 // corresponding parameter declared by the template in its
5647 // template-parameter-list.
5648 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5649 SmallVector<TemplateArgument, 2> ArgumentPack;
5650 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5651 LocalInstantiationScope InstScope(*this, true);
5652 for (TemplateParameterList::iterator Param = Params->begin(),
5653 ParamEnd = Params->end();
5654 Param != ParamEnd; /* increment in loop */) {
5655 // If we have an expanded parameter pack, make sure we don't have too
5656 // many arguments.
5657 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5658 if (*Expansions == ArgumentPack.size()) {
5659 // We're done with this parameter pack. Pack up its arguments and add
5660 // them to the list.
5661 Converted.push_back(
5662 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5663 ArgumentPack.clear();
5664
5665 // This argument is assigned to the next parameter.
5666 ++Param;
5667 continue;
5668 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5669 // Not enough arguments for this parameter pack.
5670 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5671 << /*not enough args*/0
5672 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5673 << Template;
5674 Diag(Template->getLocation(), diag::note_template_decl_here)
5675 << Params->getSourceRange();
5676 return true;
5677 }
5678 }
5679
5680 if (ArgIdx < NumArgs) {
5681 // Check the template argument we were given.
5682 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5683 TemplateLoc, RAngleLoc,
5684 ArgumentPack.size(), Converted))
5685 return true;
5686
5687 bool PackExpansionIntoNonPack =
5688 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5689 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5690 if (PackExpansionIntoNonPack && (isa<TypeAliasTemplateDecl>(Template) ||
5691 isa<ConceptDecl>(Template))) {
5692 // Core issue 1430: we have a pack expansion as an argument to an
5693 // alias template, and it's not part of a parameter pack. This
5694 // can't be canonicalized, so reject it now.
5695 // As for concepts - we cannot normalize constraints where this
5696 // situation exists.
5697 Diag(NewArgs[ArgIdx].getLocation(),
5698 diag::err_template_expansion_into_fixed_list)
5699 << (isa<ConceptDecl>(Template) ? 1 : 0)
5700 << NewArgs[ArgIdx].getSourceRange();
5701 Diag((*Param)->getLocation(), diag::note_template_param_here);
5702 return true;
5703 }
5704
5705 // We're now done with this argument.
5706 ++ArgIdx;
5707
5708 if ((*Param)->isTemplateParameterPack()) {
5709 // The template parameter was a template parameter pack, so take the
5710 // deduced argument and place it on the argument pack. Note that we
5711 // stay on the same template parameter so that we can deduce more
5712 // arguments.
5713 ArgumentPack.push_back(Converted.pop_back_val());
5714 } else {
5715 // Move to the next template parameter.
5716 ++Param;
5717 }
5718
5719 // If we just saw a pack expansion into a non-pack, then directly convert
5720 // the remaining arguments, because we don't know what parameters they'll
5721 // match up with.
5722 if (PackExpansionIntoNonPack) {
5723 if (!ArgumentPack.empty()) {
5724 // If we were part way through filling in an expanded parameter pack,
5725 // fall back to just producing individual arguments.
5726 Converted.insert(Converted.end(),
5727 ArgumentPack.begin(), ArgumentPack.end());
5728 ArgumentPack.clear();
5729 }
5730
5731 while (ArgIdx < NumArgs) {
5732 Converted.push_back(NewArgs[ArgIdx].getArgument());
5733 ++ArgIdx;
5734 }
5735
5736 return false;
5737 }
5738
5739 continue;
5740 }
5741
5742 // If we're checking a partial template argument list, we're done.
5743 if (PartialTemplateArgs) {
5744 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5745 Converted.push_back(
5746 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5747 return false;
5748 }
5749
5750 // If we have a template parameter pack with no more corresponding
5751 // arguments, just break out now and we'll fill in the argument pack below.
5752 if ((*Param)->isTemplateParameterPack()) {
5753 assert(!getExpandedPackSize(*Param) &&
5754 "Should have dealt with this already");
5755
5756 // A non-expanded parameter pack before the end of the parameter list
5757 // only occurs for an ill-formed template parameter list, unless we've
5758 // got a partial argument list for a function template, so just bail out.
5759 if (Param + 1 != ParamEnd)
5760 return true;
5761
5762 Converted.push_back(
5763 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5764 ArgumentPack.clear();
5765
5766 ++Param;
5767 continue;
5768 }
5769
5770 // Check whether we have a default argument.
5771 TemplateArgumentLoc Arg;
5772
5773 // Retrieve the default template argument from the template
5774 // parameter. For each kind of template parameter, we substitute the
5775 // template arguments provided thus far and any "outer" template arguments
5776 // (when the template parameter was part of a nested template) into
5777 // the default argument.
5778 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5779 if (!hasVisibleDefaultArgument(TTP))
5780 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5781 NewArgs);
5782
5783 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5784 Template,
5785 TemplateLoc,
5786 RAngleLoc,
5787 TTP,
5788 Converted);
5789 if (!ArgType)
5790 return true;
5791
5792 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5793 ArgType);
5794 } else if (NonTypeTemplateParmDecl *NTTP
5795 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5796 if (!hasVisibleDefaultArgument(NTTP))
5797 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5798 NewArgs);
5799
5800 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5801 TemplateLoc,
5802 RAngleLoc,
5803 NTTP,
5804 Converted);
5805 if (E.isInvalid())
5806 return true;
5807
5808 Expr *Ex = E.getAs<Expr>();
5809 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5810 } else {
5811 TemplateTemplateParmDecl *TempParm
5812 = cast<TemplateTemplateParmDecl>(*Param);
5813
5814 if (!hasVisibleDefaultArgument(TempParm))
5815 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5816 NewArgs);
5817
5818 NestedNameSpecifierLoc QualifierLoc;
5819 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5820 TemplateLoc,
5821 RAngleLoc,
5822 TempParm,
5823 Converted,
5824 QualifierLoc);
5825 if (Name.isNull())
5826 return true;
5827
5828 Arg = TemplateArgumentLoc(
5829 Context, TemplateArgument(Name), QualifierLoc,
5830 TempParm->getDefaultArgument().getTemplateNameLoc());
5831 }
5832
5833 // Introduce an instantiation record that describes where we are using
5834 // the default template argument. We're not actually instantiating a
5835 // template here, we just create this object to put a note into the
5836 // context stack.
5837 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5838 SourceRange(TemplateLoc, RAngleLoc));
5839 if (Inst.isInvalid())
5840 return true;
5841
5842 // Check the default template argument.
5843 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5844 RAngleLoc, 0, Converted))
5845 return true;
5846
5847 // Core issue 150 (assumed resolution): if this is a template template
5848 // parameter, keep track of the default template arguments from the
5849 // template definition.
5850 if (isTemplateTemplateParameter)
5851 NewArgs.addArgument(Arg);
5852
5853 // Move to the next template parameter and argument.
5854 ++Param;
5855 ++ArgIdx;
5856 }
5857
5858 // If we're performing a partial argument substitution, allow any trailing
5859 // pack expansions; they might be empty. This can happen even if
5860 // PartialTemplateArgs is false (the list of arguments is complete but
5861 // still dependent).
5862 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5863 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5864 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5865 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5866 }
5867
5868 // If we have any leftover arguments, then there were too many arguments.
5869 // Complain and fail.
5870 if (ArgIdx < NumArgs) {
5871 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5872 << /*too many args*/1
5873 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5874 << Template
5875 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5876 Diag(Template->getLocation(), diag::note_template_decl_here)
5877 << Params->getSourceRange();
5878 return true;
5879 }
5880
5881 // No problems found with the new argument list, propagate changes back
5882 // to caller.
5883 if (UpdateArgsWithConversions)
5884 TemplateArgs = std::move(NewArgs);
5885
5886 if (!PartialTemplateArgs &&
5887 EnsureTemplateArgumentListConstraints(
5888 Template, Converted, SourceRange(TemplateLoc,
5889 TemplateArgs.getRAngleLoc()))) {
5890 if (ConstraintsNotSatisfied)
5891 *ConstraintsNotSatisfied = true;
5892 return true;
5893 }
5894
5895 return false;
5896}
5897
5898namespace {
5899 class UnnamedLocalNoLinkageFinder
5900 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5901 {
5902 Sema &S;
5903 SourceRange SR;
5904
5905 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5906
5907 public:
5908 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5909
5910 bool Visit(QualType T) {
5911 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5912 }
5913
5914#define TYPE(Class, Parent) \
5915 bool Visit##Class##Type(const Class##Type *);
5916#define ABSTRACT_TYPE(Class, Parent) \
5917 bool Visit##Class##Type(const Class##Type *) { return false; }
5918#define NON_CANONICAL_TYPE(Class, Parent) \
5919 bool Visit##Class##Type(const Class##Type *) { return false; }
5920#include "clang/AST/TypeNodes.inc"
5921
5922 bool VisitTagDecl(const TagDecl *Tag);
5923 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5924 };
5925} // end anonymous namespace
5926
5927bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5928 return false;
5929}
5930
5931bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5932 return Visit(T->getElementType());
5933}
5934
5935bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5936 return Visit(T->getPointeeType());
5937}
5938
5939bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5940 const BlockPointerType* T) {
5941 return Visit(T->getPointeeType());
5942}
5943
5944bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5945 const LValueReferenceType* T) {
5946 return Visit(T->getPointeeType());
5947}
5948
5949bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5950 const RValueReferenceType* T) {
5951 return Visit(T->getPointeeType());
5952}
5953
5954bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5955 const MemberPointerType* T) {
5956 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5957}
5958
5959bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5960 const ConstantArrayType* T) {
5961 return Visit(T->getElementType());
5962}
5963
5964bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5965 const IncompleteArrayType* T) {
5966 return Visit(T->getElementType());
5967}
5968
5969bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5970 const VariableArrayType* T) {
5971 return Visit(T->getElementType());
5972}
5973
5974bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5975 const DependentSizedArrayType* T) {
5976 return Visit(T->getElementType());
5977}
5978
5979bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5980 const DependentSizedExtVectorType* T) {
5981 return Visit(T->getElementType());
5982}
5983
5984bool UnnamedLocalNoLinkageFinder::VisitDependentSizedMatrixType(
5985 const DependentSizedMatrixType *T) {
5986 return Visit(T->getElementType());
5987}
5988
5989bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5990 const DependentAddressSpaceType *T) {
5991 return Visit(T->getPointeeType());
5992}
5993
5994bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5995 return Visit(T->getElementType());
5996}
5997
5998bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5999 const DependentVectorType *T) {
6000 return Visit(T->getElementType());
6001}
6002
6003bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
6004 return Visit(T->getElementType());
6005}
6006
6007bool UnnamedLocalNoLinkageFinder::VisitConstantMatrixType(
6008 const ConstantMatrixType *T) {
6009 return Visit(T->getElementType());
6010}
6011
6012bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
6013 const FunctionProtoType* T) {
6014 for (const auto &A : T->param_types()) {
6015 if (Visit(A))
6016 return true;
6017 }
6018
6019 return Visit(T->getReturnType());
6020}
6021
6022bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
6023 const FunctionNoProtoType* T) {
6024 return Visit(T->getReturnType());
6025}
6026
6027bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
6028 const UnresolvedUsingType*) {
6029 return false;
6030}
6031
6032bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
6033 return false;
6034}
6035
6036bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
6037 return Visit(T->getUnderlyingType());
6038}
6039
6040bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
6041 return false;
6042}
6043
6044bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
6045 const UnaryTransformType*) {
6046 return false;
6047}
6048
6049bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
6050 return Visit(T->getDeducedType());
6051}
6052
6053bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
6054 const DeducedTemplateSpecializationType *T) {
6055 return Visit(T->getDeducedType());
6056}
6057
6058bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
6059 return VisitTagDecl(T->getDecl());
6060}
6061
6062bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
6063 return VisitTagDecl(T->getDecl());
6064}
6065
6066bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
6067 const TemplateTypeParmType*) {
6068 return false;
6069}
6070
6071bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
6072 const SubstTemplateTypeParmPackType *) {
6073 return false;
6074}
6075
6076bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
6077 const TemplateSpecializationType*) {
6078 return false;
6079}
6080
6081bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
6082 const InjectedClassNameType* T) {
6083 return VisitTagDecl(T->getDecl());
6084}
6085
6086bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
6087 const DependentNameType* T) {
6088 return VisitNestedNameSpecifier(T->getQualifier());
6089}
6090
6091bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
6092 const DependentTemplateSpecializationType* T) {
6093 if (auto *Q = T->getQualifier())
6094 return VisitNestedNameSpecifier(Q);
6095 return false;
6096}
6097
6098bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
6099 const PackExpansionType* T) {
6100 return Visit(T->getPattern());
6101}
6102
6103bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
6104 return false;
6105}
6106
6107bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
6108 const ObjCInterfaceType *) {
6109 return false;
6110}
6111
6112bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
6113 const ObjCObjectPointerType *) {
6114 return false;
6115}
6116
6117bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
6118 return Visit(T->getValueType());
6119}
6120
6121bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
6122 return false;
6123}
6124
6125bool UnnamedLocalNoLinkageFinder::VisitExtIntType(const ExtIntType *T) {
6126 return false;
6127}
6128
6129bool UnnamedLocalNoLinkageFinder::VisitDependentExtIntType(
6130 const DependentExtIntType *T) {
6131 return false;
6132}
6133
6134bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
6135 if (Tag->getDeclContext()->isFunctionOrMethod()) {
6136 S.Diag(SR.getBegin(),
6137 S.getLangOpts().CPlusPlus11 ?
6138 diag::warn_cxx98_compat_template_arg_local_type :
6139 diag::ext_template_arg_local_type)
6140 << S.Context.getTypeDeclType(Tag) << SR;
6141 return true;
6142 }
6143
6144 if (!Tag->hasNameForLinkage()) {
6145 S.Diag(SR.getBegin(),
6146 S.getLangOpts().CPlusPlus11 ?
6147 diag::warn_cxx98_compat_template_arg_unnamed_type :
6148 diag::ext_template_arg_unnamed_type) << SR;
6149 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
6150 return true;
6151 }
6152
6153 return false;
6154}
6155
6156bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
6157 NestedNameSpecifier *NNS) {
6158 assert(NNS);
6159 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
6160 return true;
6161
6162 switch (NNS->getKind()) {
6163 case NestedNameSpecifier::Identifier:
6164 case NestedNameSpecifier::Namespace:
6165 case NestedNameSpecifier::NamespaceAlias:
6166 case NestedNameSpecifier::Global:
6167 case NestedNameSpecifier::Super:
6168 return false;
6169
6170 case NestedNameSpecifier::TypeSpec:
6171 case NestedNameSpecifier::TypeSpecWithTemplate:
6172 return Visit(QualType(NNS->getAsType(), 0));
6173 }
6174 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
6175}
6176
6177/// Check a template argument against its corresponding
6178/// template type parameter.
6179///
6180/// This routine implements the semantics of C++ [temp.arg.type]. It
6181/// returns true if an error occurred, and false otherwise.
6182bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
6183 TypeSourceInfo *ArgInfo) {
6184 assert(ArgInfo && "invalid TypeSourceInfo");
6185 QualType Arg = ArgInfo->getType();
6186 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
6187
6188 if (Arg->isVariablyModifiedType()) {
6189 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
6190 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
6191 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
6192 }
6193
6194 // C++03 [temp.arg.type]p2:
6195 // A local type, a type with no linkage, an unnamed type or a type
6196 // compounded from any of these types shall not be used as a
6197 // template-argument for a template type-parameter.
6198 //
6199 // C++11 allows these, and even in C++03 we allow them as an extension with
6200 // a warning.
6201 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
6202 UnnamedLocalNoLinkageFinder Finder(*this, SR);
6203 (void)Finder.Visit(Context.getCanonicalType(Arg));
6204 }
6205
6206 return false;
6207}
6208
6209enum NullPointerValueKind {
6210 NPV_NotNullPointer,
6211 NPV_NullPointer,
6212 NPV_Error
6213};
6214
6215/// Determine whether the given template argument is a null pointer
6216/// value of the appropriate type.
6217static NullPointerValueKind
6218isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
6219 QualType ParamType, Expr *Arg,
6220 Decl *Entity = nullptr) {
6221 if (Arg->isValueDependent() || Arg->isTypeDependent())
6222 return NPV_NotNullPointer;
6223
6224 // dllimport'd entities aren't constant but are available inside of template
6225 // arguments.
6226 if (Entity && Entity->hasAttr<DLLImportAttr>())
6227 return NPV_NotNullPointer;
6228
6229 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
6230 llvm_unreachable(
6231 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
6232
6233 if (!S.getLangOpts().CPlusPlus11)
6234 return NPV_NotNullPointer;
6235
6236 // Determine whether we have a constant expression.
6237 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
6238 if (ArgRV.isInvalid())
6239 return NPV_Error;
6240 Arg = ArgRV.get();
6241
6242 Expr::EvalResult EvalResult;
6243 SmallVector<PartialDiagnosticAt, 8> Notes;
6244 EvalResult.Diag = &Notes;
6245 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
6246 EvalResult.HasSideEffects) {
6247 SourceLocation DiagLoc = Arg->getExprLoc();
6248
6249 // If our only note is the usual "invalid subexpression" note, just point
6250 // the caret at its location rather than producing an essentially
6251 // redundant note.
6252 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
6253 diag::note_invalid_subexpr_in_const_expr) {
6254 DiagLoc = Notes[0].first;
6255 Notes.clear();
6256 }
6257
6258 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
6259 << Arg->getType() << Arg->getSourceRange();
6260 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
6261 S.Diag(Notes[I].first, Notes[I].second);
6262
6263 S.Diag(Param->getLocation(), diag::note_template_param_here);
6264 return NPV_Error;
6265 }
6266
6267 // C++11 [temp.arg.nontype]p1:
6268 // - an address constant expression of type std::nullptr_t
6269 if (Arg->getType()->isNullPtrType())
6270 return NPV_NullPointer;
6271
6272 // - a constant expression that evaluates to a null pointer value (4.10); or
6273 // - a constant expression that evaluates to a null member pointer value
6274 // (4.11); or
6275 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
6276 (EvalResult.Val.isMemberPointer() &&
6277 !EvalResult.Val.getMemberPointerDecl())) {
6278 // If our expression has an appropriate type, we've succeeded.
6279 bool ObjCLifetimeConversion;
6280 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
6281 S.IsQualificationConversion(Arg->getType(), ParamType, false,
6282 ObjCLifetimeConversion))
6283 return NPV_NullPointer;
6284
6285 // The types didn't match, but we know we got a null pointer; complain,
6286 // then recover as if the types were correct.
6287 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
6288 << Arg->getType() << ParamType << Arg->getSourceRange();
6289 S.Diag(Param->getLocation(), diag::note_template_param_here);
6290 return NPV_NullPointer;
6291 }
6292
6293 // If we don't have a null pointer value, but we do have a NULL pointer
6294 // constant, suggest a cast to the appropriate type.
6295 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
6296 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
6297 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
6298 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
6299 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
6300 ")");
6301 S.Diag(Param->getLocation(), diag::note_template_param_here);
6302 return NPV_NullPointer;
6303 }
6304
6305 // FIXME: If we ever want to support general, address-constant expressions
6306 // as non-type template arguments, we should return the ExprResult here to
6307 // be interpreted by the caller.
6308 return NPV_NotNullPointer;
6309}
6310
6311/// Checks whether the given template argument is compatible with its
6312/// template parameter.
6313static bool CheckTemplateArgumentIsCompatibleWithParameter(
6314 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
6315 Expr *Arg, QualType ArgType) {
6316 bool ObjCLifetimeConversion;
6317 if (ParamType->isPointerType() &&
6318 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
6319 S.IsQualificationConversion(ArgType, ParamType, false,
6320 ObjCLifetimeConversion)) {
6321 // For pointer-to-object types, qualification conversions are
6322 // permitted.
6323 } else {
6324 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
6325 if (!ParamRef->getPointeeType()->isFunctionType()) {
6326 // C++ [temp.arg.nontype]p5b3:
6327 // For a non-type template-parameter of type reference to
6328 // object, no conversions apply. The type referred to by the
6329 // reference may be more cv-qualified than the (otherwise
6330 // identical) type of the template- argument. The
6331 // template-parameter is bound directly to the
6332 // template-argument, which shall be an lvalue.
6333
6334 // FIXME: Other qualifiers?
6335 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
6336 unsigned ArgQuals = ArgType.getCVRQualifiers();
6337
6338 if ((ParamQuals | ArgQuals) != ParamQuals) {
6339 S.Diag(Arg->getBeginLoc(),
6340 diag::err_template_arg_ref_bind_ignores_quals)
6341 << ParamType << Arg->getType() << Arg->getSourceRange();
6342 S.Diag(Param->getLocation(), diag::note_template_param_here);
6343 return true;
6344 }
6345 }
6346 }
6347
6348 // At this point, the template argument refers to an object or
6349 // function with external linkage. We now need to check whether the
6350 // argument and parameter types are compatible.
6351 if (!S.Context.hasSameUnqualifiedType(ArgType,
6352 ParamType.getNonReferenceType())) {
6353 // We can't perform this conversion or binding.
6354 if (ParamType->isReferenceType())
6355 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
6356 << ParamType << ArgIn->getType() << Arg->getSourceRange();
6357 else
6358 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6359 << ArgIn->getType() << ParamType << Arg->getSourceRange();
6360 S.Diag(Param->getLocation(), diag::note_template_param_here);
6361 return true;
6362 }
6363 }
6364
6365 return false;
6366}
6367
6368/// Checks whether the given template argument is the address
6369/// of an object or function according to C++ [temp.arg.nontype]p1.
6370static bool
6371CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
6372 NonTypeTemplateParmDecl *Param,
6373 QualType ParamType,
6374 Expr *ArgIn,
6375 TemplateArgument &Converted) {
6376 bool Invalid = false;
6377 Expr *Arg = ArgIn;
6378 QualType ArgType = Arg->getType();
6379
6380 bool AddressTaken = false;
6381 SourceLocation AddrOpLoc;
6382 if (S.getLangOpts().MicrosoftExt) {
6383 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
6384 // dereference and address-of operators.
6385 Arg = Arg->IgnoreParenCasts();
6386
6387 bool ExtWarnMSTemplateArg = false;
6388 UnaryOperatorKind FirstOpKind;
6389 SourceLocation FirstOpLoc;
6390 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6391 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
6392 if (UnOpKind == UO_Deref)
6393 ExtWarnMSTemplateArg = true;
6394 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
6395 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
6396 if (!AddrOpLoc.isValid()) {
6397 FirstOpKind = UnOpKind;
6398 FirstOpLoc = UnOp->getOperatorLoc();
6399 }
6400 } else
6401 break;
6402 }
6403 if (FirstOpLoc.isValid()) {
6404 if (ExtWarnMSTemplateArg)
6405 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
6406 << ArgIn->getSourceRange();
6407
6408 if (FirstOpKind == UO_AddrOf)
6409 AddressTaken = true;
6410 else if (Arg->getType()->isPointerType()) {
6411 // We cannot let pointers get dereferenced here, that is obviously not a
6412 // constant expression.
6413 assert(FirstOpKind == UO_Deref);
6414 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6415 << Arg->getSourceRange();
6416 }
6417 }
6418 } else {
6419 // See through any implicit casts we added to fix the type.
6420 Arg = Arg->IgnoreImpCasts();
6421
6422 // C++ [temp.arg.nontype]p1:
6423 //
6424 // A template-argument for a non-type, non-template
6425 // template-parameter shall be one of: [...]
6426 //
6427 // -- the address of an object or function with external
6428 // linkage, including function templates and function
6429 // template-ids but excluding non-static class members,
6430 // expressed as & id-expression where the & is optional if
6431 // the name refers to a function or array, or if the
6432 // corresponding template-parameter is a reference; or
6433
6434 // In C++98/03 mode, give an extension warning on any extra parentheses.
6435 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6436 bool ExtraParens = false;
6437 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6438 if (!Invalid && !ExtraParens) {
6439 S.Diag(Arg->getBeginLoc(),
6440 S.getLangOpts().CPlusPlus11
6441 ? diag::warn_cxx98_compat_template_arg_extra_parens
6442 : diag::ext_template_arg_extra_parens)
6443 << Arg->getSourceRange();
6444 ExtraParens = true;
6445 }
6446
6447 Arg = Parens->getSubExpr();
6448 }
6449
6450 while (SubstNonTypeTemplateParmExpr *subst =
6451 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6452 Arg = subst->getReplacement()->IgnoreImpCasts();
6453
6454 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6455 if (UnOp->getOpcode() == UO_AddrOf) {
6456 Arg = UnOp->getSubExpr();
6457 AddressTaken = true;
6458 AddrOpLoc = UnOp->getOperatorLoc();
6459 }
6460 }
6461
6462 while (SubstNonTypeTemplateParmExpr *subst =
6463 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6464 Arg = subst->getReplacement()->IgnoreImpCasts();
6465 }
6466
6467 ValueDecl *Entity = nullptr;
6468 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg))
6469 Entity = DRE->getDecl();
6470 else if (CXXUuidofExpr *CUE = dyn_cast<CXXUuidofExpr>(Arg))
6471 Entity = CUE->getGuidDecl();
6472
6473 // If our parameter has pointer type, check for a null template value.
6474 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6475 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6476 Entity)) {
6477 case NPV_NullPointer:
6478 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6479 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6480 /*isNullPtr=*/true);
6481 return false;
6482
6483 case NPV_Error:
6484 return true;
6485
6486 case NPV_NotNullPointer:
6487 break;
6488 }
6489 }
6490
6491 // Stop checking the precise nature of the argument if it is value dependent,
6492 // it should be checked when instantiated.
6493 if (Arg->isValueDependent()) {
6494 Converted = TemplateArgument(ArgIn);
6495 return false;
6496 }
6497
6498 if (!Entity) {
6499 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6500 << Arg->getSourceRange();
6501 S.Diag(Param->getLocation(), diag::note_template_param_here);
6502 return true;
6503 }
6504
6505 // Cannot refer to non-static data members
6506 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6507 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6508 << Entity << Arg->getSourceRange();
6509 S.Diag(Param->getLocation(), diag::note_template_param_here);
6510 return true;
6511 }
6512
6513 // Cannot refer to non-static member functions
6514 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6515 if (!Method->isStatic()) {
6516 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6517 << Method << Arg->getSourceRange();
6518 S.Diag(Param->getLocation(), diag::note_template_param_here);
6519 return true;
6520 }
6521 }
6522
6523 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6524 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6525 MSGuidDecl *Guid = dyn_cast<MSGuidDecl>(Entity);
6526
6527 // A non-type template argument must refer to an object or function.
6528 if (!Func && !Var && !Guid) {
6529 // We found something, but we don't know specifically what it is.
6530 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6531 << Arg->getSourceRange();
6532 S.Diag(Entity->getLocation(), diag::note_template_arg_refers_here);
6533 return true;
6534 }
6535
6536 // Address / reference template args must have external linkage in C++98.
6537 if (Entity->getFormalLinkage() == InternalLinkage) {
6538 S.Diag(Arg->getBeginLoc(),
6539 S.getLangOpts().CPlusPlus11
6540 ? diag::warn_cxx98_compat_template_arg_object_internal
6541 : diag::ext_template_arg_object_internal)
6542 << !Func << Entity << Arg->getSourceRange();
6543 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6544 << !Func;
6545 } else if (!Entity->hasLinkage()) {
6546 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6547 << !Func << Entity << Arg->getSourceRange();
6548 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6549 << !Func;
6550 return true;
6551 }
6552
6553 if (Var) {
6554 // A value of reference type is not an object.
6555 if (Var->getType()->isReferenceType()) {
6556 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6557 << Var->getType() << Arg->getSourceRange();
6558 S.Diag(Param->getLocation(), diag::note_template_param_here);
6559 return true;
6560 }
6561
6562 // A template argument must have static storage duration.
6563 if (Var->getTLSKind()) {
6564 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6565 << Arg->getSourceRange();
6566 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6567 return true;
6568 }
6569 }
6570
6571 if (AddressTaken && ParamType->isReferenceType()) {
6572 // If we originally had an address-of operator, but the
6573 // parameter has reference type, complain and (if things look
6574 // like they will work) drop the address-of operator.
6575 if (!S.Context.hasSameUnqualifiedType(Entity->getType(),
6576 ParamType.getNonReferenceType())) {
6577 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6578 << ParamType;
6579 S.Diag(Param->getLocation(), diag::note_template_param_here);
6580 return true;
6581 }
6582
6583 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6584 << ParamType
6585 << FixItHint::CreateRemoval(AddrOpLoc);
6586 S.Diag(Param->getLocation(), diag::note_template_param_here);
6587
6588 ArgType = Entity->getType();
6589 }
6590
6591 // If the template parameter has pointer type, either we must have taken the
6592 // address or the argument must decay to a pointer.
6593 if (!AddressTaken && ParamType->isPointerType()) {
6594 if (Func) {
6595 // Function-to-pointer decay.
6596 ArgType = S.Context.getPointerType(Func->getType());
6597 } else if (Entity->getType()->isArrayType()) {
6598 // Array-to-pointer decay.
6599 ArgType = S.Context.getArrayDecayedType(Entity->getType());
6600 } else {
6601 // If the template parameter has pointer type but the address of
6602 // this object was not taken, complain and (possibly) recover by
6603 // taking the address of the entity.
6604 ArgType = S.Context.getPointerType(Entity->getType());
6605 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6606 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6607 << ParamType;
6608 S.Diag(Param->getLocation(), diag::note_template_param_here);
6609 return true;
6610 }
6611
6612 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6613 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6614
6615 S.Diag(Param->getLocation(), diag::note_template_param_here);
6616 }
6617 }
6618
6619 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6620 Arg, ArgType))
6621 return true;
6622
6623 // Create the template argument.
6624 Converted = TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()),
6625 S.Context.getCanonicalType(ParamType));
6626 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6627 return false;
6628}
6629
6630/// Checks whether the given template argument is a pointer to
6631/// member constant according to C++ [temp.arg.nontype]p1.
6632static bool CheckTemplateArgumentPointerToMember(Sema &S,
6633 NonTypeTemplateParmDecl *Param,
6634 QualType ParamType,
6635 Expr *&ResultArg,
6636 TemplateArgument &Converted) {
6637 bool Invalid = false;
6638
6639 Expr *Arg = ResultArg;
6640 bool ObjCLifetimeConversion;
6641
6642 // C++ [temp.arg.nontype]p1:
6643 //
6644 // A template-argument for a non-type, non-template
6645 // template-parameter shall be one of: [...]
6646 //
6647 // -- a pointer to member expressed as described in 5.3.1.
6648 DeclRefExpr *DRE = nullptr;
6649
6650 // In C++98/03 mode, give an extension warning on any extra parentheses.
6651 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6652 bool ExtraParens = false;
6653 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6654 if (!Invalid && !ExtraParens) {
6655 S.Diag(Arg->getBeginLoc(),
6656 S.getLangOpts().CPlusPlus11
6657 ? diag::warn_cxx98_compat_template_arg_extra_parens
6658 : diag::ext_template_arg_extra_parens)
6659 << Arg->getSourceRange();
6660 ExtraParens = true;
6661 }
6662
6663 Arg = Parens->getSubExpr();
6664 }
6665
6666 while (SubstNonTypeTemplateParmExpr *subst =
6667 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6668 Arg = subst->getReplacement()->IgnoreImpCasts();
6669
6670 // A pointer-to-member constant written &Class::member.
6671 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6672 if (UnOp->getOpcode() == UO_AddrOf) {
6673 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6674 if (DRE && !DRE->getQualifier())
6675 DRE = nullptr;
6676 }
6677 }
6678 // A constant of pointer-to-member type.
6679 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6680 ValueDecl *VD = DRE->getDecl();
6681 if (VD->getType()->isMemberPointerType()) {
6682 if (isa<NonTypeTemplateParmDecl>(VD)) {
6683 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6684 Converted = TemplateArgument(Arg);
6685 } else {
6686 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6687 Converted = TemplateArgument(VD, ParamType);
6688 }
6689 return Invalid;
6690 }
6691 }
6692
6693 DRE = nullptr;
6694 }
6695
6696 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6697
6698 // Check for a null pointer value.
6699 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6700 Entity)) {
6701 case NPV_Error:
6702 return true;
6703 case NPV_NullPointer:
6704 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6705 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6706 /*isNullPtr*/true);
6707 return false;
6708 case NPV_NotNullPointer:
6709 break;
6710 }
6711
6712 if (S.IsQualificationConversion(ResultArg->getType(),
6713 ParamType.getNonReferenceType(), false,
6714 ObjCLifetimeConversion)) {
6715 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6716 ResultArg->getValueKind())
6717 .get();
6718 } else if (!S.Context.hasSameUnqualifiedType(
6719 ResultArg->getType(), ParamType.getNonReferenceType())) {
6720 // We can't perform this conversion.
6721 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6722 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6723 S.Diag(Param->getLocation(), diag::note_template_param_here);
6724 return true;
6725 }
6726
6727 if (!DRE)
6728 return S.Diag(Arg->getBeginLoc(),
6729 diag::err_template_arg_not_pointer_to_member_form)
6730 << Arg->getSourceRange();
6731
6732 if (isa<FieldDecl>(DRE->getDecl()) ||
6733 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6734 isa<CXXMethodDecl>(DRE->getDecl())) {
6735 assert((isa<FieldDecl>(DRE->getDecl()) ||
6736 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6737 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6738 "Only non-static member pointers can make it here");
6739
6740 // Okay: this is the address of a non-static member, and therefore
6741 // a member pointer constant.
6742 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6743 Converted = TemplateArgument(Arg);
6744 } else {
6745 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6746 Converted = TemplateArgument(D, S.Context.getCanonicalType(ParamType));
6747 }
6748 return Invalid;
6749 }
6750
6751 // We found something else, but we don't know specifically what it is.
6752 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6753 << Arg->getSourceRange();
6754 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6755 return true;
6756}
6757
6758/// Check a template argument against its corresponding
6759/// non-type template parameter.
6760///
6761/// This routine implements the semantics of C++ [temp.arg.nontype].
6762/// If an error occurred, it returns ExprError(); otherwise, it
6763/// returns the converted template argument. \p ParamType is the
6764/// type of the non-type template parameter after it has been instantiated.
6765ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6766 QualType ParamType, Expr *Arg,
6767 TemplateArgument &Converted,
6768 CheckTemplateArgumentKind CTAK) {
6769 SourceLocation StartLoc = Arg->getBeginLoc();
6770
6771 // If the parameter type somehow involves auto, deduce the type now.
6772 DeducedType *DeducedT = ParamType->getContainedDeducedType();
6773 if (getLangOpts().CPlusPlus17 && DeducedT && !DeducedT->isDeduced()) {
6774 // During template argument deduction, we allow 'decltype(auto)' to
6775 // match an arbitrary dependent argument.
6776 // FIXME: The language rules don't say what happens in this case.
6777 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6778 // expression is merely instantiation-dependent; is this enough?
6779 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6780 auto *AT = dyn_cast<AutoType>(DeducedT);
6781 if (AT && AT->isDecltypeAuto()) {
6782 Converted = TemplateArgument(Arg);
6783 return Arg;
6784 }
6785 }
6786
6787 // When checking a deduced template argument, deduce from its type even if
6788 // the type is dependent, in order to check the types of non-type template
6789 // arguments line up properly in partial ordering.
6790 Optional<unsigned> Depth = Param->getDepth() + 1;
6791 Expr *DeductionArg = Arg;
6792 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6793 DeductionArg = PE->getPattern();
6794 TypeSourceInfo *TSI =
6795 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation());
6796 if (isa<DeducedTemplateSpecializationType>(DeducedT)) {
6797 InitializedEntity Entity =
6798 InitializedEntity::InitializeTemplateParameter(ParamType, Param);
6799 InitializationKind Kind = InitializationKind::CreateForInit(
6800 DeductionArg->getBeginLoc(), /*DirectInit*/false, DeductionArg);
6801 Expr *Inits[1] = {DeductionArg};
6802 ParamType =
6803 DeduceTemplateSpecializationFromInitializer(TSI, Entity, Kind, Inits);
6804 if (ParamType.isNull())
6805 return ExprError();
6806 } else if (DeduceAutoType(
6807 TSI, DeductionArg, ParamType, Depth,
6808 // We do not check constraints right now because the
6809 // immediately-declared constraint of the auto type is also
6810 // an associated constraint, and will be checked along with
6811 // the other associated constraints after checking the
6812 // template argument list.
6813 /*IgnoreConstraints=*/true) == DAR_Failed) {
6814 Diag(Arg->getExprLoc(),
6815 diag::err_non_type_template_parm_type_deduction_failure)
6816 << Param->getDeclName() << Param->getType() << Arg->getType()
6817 << Arg->getSourceRange();
6818 Diag(Param->getLocation(), diag::note_template_param_here);
6819 return ExprError();
6820 }
6821 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6822 // an error. The error message normally references the parameter
6823 // declaration, but here we'll pass the argument location because that's
6824 // where the parameter type is deduced.
6825 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6826 if (ParamType.isNull()) {
6827 Diag(Param->getLocation(), diag::note_template_param_here);
6828 return ExprError();
6829 }
6830 }
6831
6832 // We should have already dropped all cv-qualifiers by now.
6833 assert(!ParamType.hasQualifiers() &&
6834 "non-type template parameter type cannot be qualified");
6835
6836 // FIXME: When Param is a reference, should we check that Arg is an lvalue?
6837 if (CTAK == CTAK_Deduced &&
6838 (ParamType->isReferenceType()
6839 ? !Context.hasSameType(ParamType.getNonReferenceType(),
6840 Arg->getType())
6841 : !Context.hasSameUnqualifiedType(ParamType, Arg->getType()))) {
6842 // FIXME: If either type is dependent, we skip the check. This isn't
6843 // correct, since during deduction we're supposed to have replaced each
6844 // template parameter with some unique (non-dependent) placeholder.
6845 // FIXME: If the argument type contains 'auto', we carry on and fail the
6846 // type check in order to force specific types to be more specialized than
6847 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6848 // work. Similarly for CTAD, when comparing 'A<x>' against 'A'.
6849 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6850 !Arg->getType()->getContainedDeducedType()) {
6851 Converted = TemplateArgument(Arg);
6852 return Arg;
6853 }
6854 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6855 // we should actually be checking the type of the template argument in P,
6856 // not the type of the template argument deduced from A, against the
6857 // template parameter type.
6858 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6859 << Arg->getType()
6860 << ParamType.getUnqualifiedType();
6861 Diag(Param->getLocation(), diag::note_template_param_here);
6862 return ExprError();
6863 }
6864
6865 // If either the parameter has a dependent type or the argument is
6866 // type-dependent, there's nothing we can check now. The argument only
6867 // contains an unexpanded pack during partial ordering, and there's
6868 // nothing more we can check in that case.
6869 if (ParamType->isDependentType() || Arg->isTypeDependent() ||
6870 Arg->containsUnexpandedParameterPack()) {
6871 // Force the argument to the type of the parameter to maintain invariants.
6872 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6873 if (PE)
6874 Arg = PE->getPattern();
6875 ExprResult E = ImpCastExprToType(
6876 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6877 ParamType->isLValueReferenceType() ? VK_LValue :
6878 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6879 if (E.isInvalid())
6880 return ExprError();
6881 if (PE) {
6882 // Recreate a pack expansion if we unwrapped one.
6883 E = new (Context)
6884 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6885 PE->getNumExpansions());
6886 }
6887 Converted = TemplateArgument(E.get());
6888 return E;
6889 }
6890
6891 // The initialization of the parameter from the argument is
6892 // a constant-evaluated context.
6893 EnterExpressionEvaluationContext ConstantEvaluated(
6894 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6895
6896 if (getLangOpts().CPlusPlus17) {
6897 QualType CanonParamType = Context.getCanonicalType(ParamType);
6898
6899 // Avoid making a copy when initializing a template parameter of class type
6900 // from a template parameter object of the same type. This is going beyond
6901 // the standard, but is required for soundness: in
6902 // template<A a> struct X { X *p; X<a> *q; };
6903 // ... we need p and q to have the same type.
6904 //
6905 // Similarly, don't inject a call to a copy constructor when initializing
6906 // from a template parameter of the same type.
6907 Expr *InnerArg = Arg->IgnoreParenImpCasts();
6908 if (ParamType->isRecordType() && isa<DeclRefExpr>(InnerArg) &&
6909 Context.hasSameUnqualifiedType(ParamType, InnerArg->getType())) {
6910 NamedDecl *ND = cast<DeclRefExpr>(InnerArg)->getDecl();
6911 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(ND)) {
6912 Converted = TemplateArgument(TPO, CanonParamType);
6913 return Arg;
6914 }
6915 if (isa<NonTypeTemplateParmDecl>(ND)) {
6916 Converted = TemplateArgument(Arg);
6917 return Arg;
6918 }
6919 }
6920
6921 // C++17 [temp.arg.nontype]p1:
6922 // A template-argument for a non-type template parameter shall be
6923 // a converted constant expression of the type of the template-parameter.
6924 APValue Value;
6925 ExprResult ArgResult = CheckConvertedConstantExpression(
6926 Arg, ParamType, Value, CCEK_TemplateArg, Param);
6927 if (ArgResult.isInvalid())
6928 return ExprError();
6929
6930 // For a value-dependent argument, CheckConvertedConstantExpression is
6931 // permitted (and expected) to be unable to determine a value.
6932 if (ArgResult.get()->isValueDependent()) {
6933 Converted = TemplateArgument(ArgResult.get());
6934 return ArgResult;
6935 }
6936
6937 // Convert the APValue to a TemplateArgument.
6938 switch (Value.getKind()) {
6939 case APValue::None:
6940 assert(ParamType->isNullPtrType());
6941 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6942 break;
6943 case APValue::Indeterminate:
6944 llvm_unreachable("result of constant evaluation should be initialized");
6945 break;
6946 case APValue::Int:
6947 assert(ParamType->isIntegralOrEnumerationType());
6948 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6949 break;
6950 case APValue::MemberPointer: {
6951 assert(ParamType->isMemberPointerType());
6952
6953 // FIXME: We need TemplateArgument representation and mangling for these.
6954 if (!Value.getMemberPointerPath().empty()) {
6955 Diag(Arg->getBeginLoc(),
6956 diag::err_template_arg_member_ptr_base_derived_not_supported)
6957 << Value.getMemberPointerDecl() << ParamType
6958 << Arg->getSourceRange();
6959 return ExprError();
6960 }
6961
6962 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6963 Converted = VD ? TemplateArgument(VD, CanonParamType)
6964 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6965 break;
6966 }
6967 case APValue::LValue: {
6968 // For a non-type template-parameter of pointer or reference type,
6969 // the value of the constant expression shall not refer to
6970 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6971 ParamType->isNullPtrType());
6972 // -- a temporary object
6973 // -- a string literal
6974 // -- the result of a typeid expression, or
6975 // -- a predefined __func__ variable
6976 APValue::LValueBase Base = Value.getLValueBase();
6977 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6978 if (Base && (!VD || isa<LifetimeExtendedTemporaryDecl>(VD))) {
6979 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6980 << Arg->getSourceRange();
6981 return ExprError();
6982 }
6983 // -- a subobject
6984 // FIXME: Until C++20
6985 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6986 VD && VD->getType()->isArrayType() &&
6987 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6988 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6989 // Per defect report (no number yet):
6990 // ... other than a pointer to the first element of a complete array
6991 // object.
6992 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6993 Value.isLValueOnePastTheEnd()) {
6994 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6995 << Value.getAsString(Context, ParamType);
6996 return ExprError();
6997 }
6998 assert((VD || !ParamType->isReferenceType()) &&
6999 "null reference should not be a constant expression");
7000 assert((!VD || !ParamType->isNullPtrType()) &&
7001 "non-null value of type nullptr_t?");
7002 Converted = VD ? TemplateArgument(VD, CanonParamType)
7003 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
7004 break;
7005 }
7006 case APValue::Struct:
7007 case APValue::Union:
7008 // Get or create the corresponding template parameter object.
7009 Converted = TemplateArgument(
7010 Context.getTemplateParamObjectDecl(CanonParamType, Value),
7011 CanonParamType);
7012 break;
7013 case APValue::AddrLabelDiff:
7014 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
7015 case APValue::FixedPoint:
7016 case APValue::Float:
7017 case APValue::ComplexInt:
7018 case APValue::ComplexFloat:
7019 case APValue::Vector:
7020 case APValue::Array:
7021 return Diag(StartLoc, diag::err_non_type_template_arg_unsupported)
7022 << ParamType;
7023 }
7024
7025 return ArgResult.get();
7026 }
7027
7028 // C++ [temp.arg.nontype]p5:
7029 // The following conversions are performed on each expression used
7030 // as a non-type template-argument. If a non-type
7031 // template-argument cannot be converted to the type of the
7032 // corresponding template-parameter then the program is
7033 // ill-formed.
7034 if (ParamType->isIntegralOrEnumerationType()) {
7035 // C++11:
7036 // -- for a non-type template-parameter of integral or
7037 // enumeration type, conversions permitted in a converted
7038 // constant expression are applied.
7039 //
7040 // C++98:
7041 // -- for a non-type template-parameter of integral or
7042 // enumeration type, integral promotions (4.5) and integral
7043 // conversions (4.7) are applied.
7044
7045 if (getLangOpts().CPlusPlus11) {
7046 // C++ [temp.arg.nontype]p1:
7047 // A template-argument for a non-type, non-template template-parameter
7048 // shall be one of:
7049 //
7050 // -- for a non-type template-parameter of integral or enumeration
7051 // type, a converted constant expression of the type of the
7052 // template-parameter; or
7053 llvm::APSInt Value;
7054 ExprResult ArgResult =
7055 CheckConvertedConstantExpression(Arg, ParamType, Value,
7056 CCEK_TemplateArg);
7057 if (ArgResult.isInvalid())
7058 return ExprError();
7059
7060 // We can't check arbitrary value-dependent arguments.
7061 if (ArgResult.get()->isValueDependent()) {
7062 Converted = TemplateArgument(ArgResult.get());
7063 return ArgResult;
7064 }
7065
7066 // Widen the argument value to sizeof(parameter type). This is almost
7067 // always a no-op, except when the parameter type is bool. In
7068 // that case, this may extend the argument from 1 bit to 8 bits.
7069 QualType IntegerType = ParamType;
7070 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
7071 IntegerType = Enum->getDecl()->getIntegerType();
7072 Value = Value.extOrTrunc(IntegerType->isExtIntType()
7073 ? Context.getIntWidth(IntegerType)
7074 : Context.getTypeSize(IntegerType));
7075
7076 Converted = TemplateArgument(Context, Value,
7077 Context.getCanonicalType(ParamType));
7078 return ArgResult;
7079 }
7080
7081 ExprResult ArgResult = DefaultLvalueConversion(Arg);
7082 if (ArgResult.isInvalid())
7083 return ExprError();
7084 Arg = ArgResult.get();
7085
7086 QualType ArgType = Arg->getType();
7087
7088 // C++ [temp.arg.nontype]p1:
7089 // A template-argument for a non-type, non-template
7090 // template-parameter shall be one of:
7091 //
7092 // -- an integral constant-expression of integral or enumeration
7093 // type; or
7094 // -- the name of a non-type template-parameter; or
7095 llvm::APSInt Value;
7096 if (!ArgType->isIntegralOrEnumerationType()) {
7097 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
7098 << ArgType << Arg->getSourceRange();
7099 Diag(Param->getLocation(), diag::note_template_param_here);
7100 return ExprError();
7101 } else if (!Arg->isValueDependent()) {
7102 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
7103 QualType T;
7104
7105 public:
7106 TmplArgICEDiagnoser(QualType T) : T(T) { }
7107
7108 SemaDiagnosticBuilder diagnoseNotICE(Sema &S,
7109 SourceLocation Loc) override {
7110 return S.Diag(Loc, diag::err_template_arg_not_ice) << T;
7111 }
7112 } Diagnoser(ArgType);
7113
7114 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser).get();
7115 if (!Arg)
7116 return ExprError();
7117 }
7118
7119 // From here on out, all we care about is the unqualified form
7120 // of the argument type.
7121 ArgType = ArgType.getUnqualifiedType();
7122
7123 // Try to convert the argument to the parameter's type.
7124 if (Context.hasSameType(ParamType, ArgType)) {
7125 // Okay: no conversion necessary
7126 } else if (ParamType->isBooleanType()) {
7127 // This is an integral-to-boolean conversion.
7128 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
7129 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
7130 !ParamType->isEnumeralType()) {
7131 // This is an integral promotion or conversion.
7132 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
7133 } else {
7134 // We can't perform this conversion.
7135 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
7136 << Arg->getType() << ParamType << Arg->getSourceRange();
7137 Diag(Param->getLocation(), diag::note_template_param_here);
7138 return ExprError();
7139 }
7140
7141 // Add the value of this argument to the list of converted
7142 // arguments. We use the bitwidth and signedness of the template
7143 // parameter.
7144 if (Arg->isValueDependent()) {
7145 // The argument is value-dependent. Create a new
7146 // TemplateArgument with the converted expression.
7147 Converted = TemplateArgument(Arg);
7148 return Arg;
7149 }
7150
7151 QualType IntegerType = Context.getCanonicalType(ParamType);
7152 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
7153 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
7154
7155 if (ParamType->isBooleanType()) {
7156 // Value must be zero or one.
7157 Value = Value != 0;
7158 unsigned AllowedBits = Context.getTypeSize(IntegerType);
7159 if (Value.getBitWidth() != AllowedBits)
7160 Value = Value.extOrTrunc(AllowedBits);
7161 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7162 } else {
7163 llvm::APSInt OldValue = Value;
7164
7165 // Coerce the template argument's value to the value it will have
7166 // based on the template parameter's type.
7167 unsigned AllowedBits = IntegerType->isExtIntType()
7168 ? Context.getIntWidth(IntegerType)
7169 : Context.getTypeSize(IntegerType);
7170 if (Value.getBitWidth() != AllowedBits)
7171 Value = Value.extOrTrunc(AllowedBits);
7172 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
7173
7174 // Complain if an unsigned parameter received a negative value.
7175 if (IntegerType->isUnsignedIntegerOrEnumerationType()
7176 && (OldValue.isSigned() && OldValue.isNegative())) {
7177 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
7178 << OldValue.toString(10) << Value.toString(10) << Param->getType()
7179 << Arg->getSourceRange();
7180 Diag(Param->getLocation(), diag::note_template_param_here);
7181 }
7182
7183 // Complain if we overflowed the template parameter's type.
7184 unsigned RequiredBits;
7185 if (IntegerType->isUnsignedIntegerOrEnumerationType())
7186 RequiredBits = OldValue.getActiveBits();
7187 else if (OldValue.isUnsigned())
7188 RequiredBits = OldValue.getActiveBits() + 1;
7189 else
7190 RequiredBits = OldValue.getMinSignedBits();
7191 if (RequiredBits > AllowedBits) {
7192 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
7193 << OldValue.toString(10) << Value.toString(10) << Param->getType()
7194 << Arg->getSourceRange();
7195 Diag(Param->getLocation(), diag::note_template_param_here);
7196 }
7197 }
7198
7199 Converted = TemplateArgument(Context, Value,
7200 ParamType->isEnumeralType()
7201 ? Context.getCanonicalType(ParamType)
7202 : IntegerType);
7203 return Arg;
7204 }
7205
7206 QualType ArgType = Arg->getType();
7207 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
7208
7209 // Handle pointer-to-function, reference-to-function, and
7210 // pointer-to-member-function all in (roughly) the same way.
7211 if (// -- For a non-type template-parameter of type pointer to
7212 // function, only the function-to-pointer conversion (4.3) is
7213 // applied. If the template-argument represents a set of
7214 // overloaded functions (or a pointer to such), the matching
7215 // function is selected from the set (13.4).
7216 (ParamType->isPointerType() &&
7217 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
7218 // -- For a non-type template-parameter of type reference to
7219 // function, no conversions apply. If the template-argument
7220 // represents a set of overloaded functions, the matching
7221 // function is selected from the set (13.4).
7222 (ParamType->isReferenceType() &&
7223 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
7224 // -- For a non-type template-parameter of type pointer to
7225 // member function, no conversions apply. If the
7226 // template-argument represents a set of overloaded member
7227 // functions, the matching member function is selected from
7228 // the set (13.4).
7229 (ParamType->isMemberPointerType() &&
7230 ParamType->castAs<MemberPointerType>()->getPointeeType()
7231 ->isFunctionType())) {
7232
7233 if (Arg->getType() == Context.OverloadTy) {
7234 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
7235 true,
7236 FoundResult)) {
7237 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7238 return ExprError();
7239
7240 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7241 ArgType = Arg->getType();
7242 } else
7243 return ExprError();
7244 }
7245
7246 if (!ParamType->isMemberPointerType()) {
7247 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7248 ParamType,
7249 Arg, Converted))
7250 return ExprError();
7251 return Arg;
7252 }
7253
7254 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7255 Converted))
7256 return ExprError();
7257 return Arg;
7258 }
7259
7260 if (ParamType->isPointerType()) {
7261 // -- for a non-type template-parameter of type pointer to
7262 // object, qualification conversions (4.4) and the
7263 // array-to-pointer conversion (4.2) are applied.
7264 // C++0x also allows a value of std::nullptr_t.
7265 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
7266 "Only object pointers allowed here");
7267
7268 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7269 ParamType,
7270 Arg, Converted))
7271 return ExprError();
7272 return Arg;
7273 }
7274
7275 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
7276 // -- For a non-type template-parameter of type reference to
7277 // object, no conversions apply. The type referred to by the
7278 // reference may be more cv-qualified than the (otherwise
7279 // identical) type of the template-argument. The
7280 // template-parameter is bound directly to the
7281 // template-argument, which must be an lvalue.
7282 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
7283 "Only object references allowed here");
7284
7285 if (Arg->getType() == Context.OverloadTy) {
7286 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
7287 ParamRefType->getPointeeType(),
7288 true,
7289 FoundResult)) {
7290 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
7291 return ExprError();
7292
7293 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
7294 ArgType = Arg->getType();
7295 } else
7296 return ExprError();
7297 }
7298
7299 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
7300 ParamType,
7301 Arg, Converted))
7302 return ExprError();
7303 return Arg;
7304 }
7305
7306 // Deal with parameters of type std::nullptr_t.
7307 if (ParamType->isNullPtrType()) {
7308 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
7309 Converted = TemplateArgument(Arg);
7310 return Arg;
7311 }
7312
7313 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
7314 case NPV_NotNullPointer:
7315 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
7316 << Arg->getType() << ParamType;
7317 Diag(Param->getLocation(), diag::note_template_param_here);
7318 return ExprError();
7319
7320 case NPV_Error:
7321 return ExprError();
7322
7323 case NPV_NullPointer:
7324 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
7325 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
7326 /*isNullPtr*/true);
7327 return Arg;
7328 }
7329 }
7330
7331 // -- For a non-type template-parameter of type pointer to data
7332 // member, qualification conversions (4.4) are applied.
7333 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
7334
7335 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
7336 Converted))
7337 return ExprError();
7338 return Arg;
7339}
7340
7341static void DiagnoseTemplateParameterListArityMismatch(
7342 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
7343 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
7344
7345/// Check a template argument against its corresponding
7346/// template template parameter.
7347///
7348/// This routine implements the semantics of C++ [temp.arg.template].
7349/// It returns true if an error occurred, and false otherwise.
7350bool Sema::CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
7351 TemplateParameterList *Params,
7352 TemplateArgumentLoc &Arg) {
7353 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
7354 TemplateDecl *Template = Name.getAsTemplateDecl();
7355 if (!Template) {
7356 // Any dependent template name is fine.
7357 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
7358 return false;
7359 }
7360
7361 if (Template->isInvalidDecl())
7362 return true;
7363
7364 // C++0x [temp.arg.template]p1:
7365 // A template-argument for a template template-parameter shall be
7366 // the name of a class template or an alias template, expressed as an
7367 // id-expression. When the template-argument names a class template, only
7368 // primary class templates are considered when matching the
7369 // template template argument with the corresponding parameter;
7370 // partial specializations are not considered even if their
7371 // parameter lists match that of the template template parameter.
7372 //
7373 // Note that we also allow template template parameters here, which
7374 // will happen when we are dealing with, e.g., class template
7375 // partial specializations.
7376 if (!isa<ClassTemplateDecl>(Template) &&
7377 !isa<TemplateTemplateParmDecl>(Template) &&
7378 !isa<TypeAliasTemplateDecl>(Template) &&
7379 !isa<BuiltinTemplateDecl>(Template)) {
7380 assert(isa<FunctionTemplateDecl>(Template) &&
7381 "Only function templates are possible here");
7382 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
7383 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
7384 << Template;
7385 }
7386
7387 // C++1z [temp.arg.template]p3: (DR 150)
7388 // A template-argument matches a template template-parameter P when P
7389 // is at least as specialized as the template-argument A.
7390 // FIXME: We should enable RelaxedTemplateTemplateArgs by default as it is a
7391 // defect report resolution from C++17 and shouldn't be introduced by
7392 // concepts.
7393 if (getLangOpts().RelaxedTemplateTemplateArgs) {
7394 // Quick check for the common case:
7395 // If P contains a parameter pack, then A [...] matches P if each of A's
7396 // template parameters matches the corresponding template parameter in
7397 // the template-parameter-list of P.
7398 if (TemplateParameterListsAreEqual(
7399 Template->getTemplateParameters(), Params, false,
7400 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()) &&
7401 // If the argument has no associated constraints, then the parameter is
7402 // definitely at least as specialized as the argument.
7403 // Otherwise - we need a more thorough check.
7404 !Template->hasAssociatedConstraints())
7405 return false;
7406
7407 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
7408 Arg.getLocation())) {
7409 // C++2a[temp.func.order]p2
7410 // [...] If both deductions succeed, the partial ordering selects the
7411 // more constrained template as described by the rules in
7412 // [temp.constr.order].
7413 SmallVector<const Expr *, 3> ParamsAC, TemplateAC;
7414 Params->getAssociatedConstraints(ParamsAC);
7415 // C++2a[temp.arg.template]p3
7416 // [...] In this comparison, if P is unconstrained, the constraints on A
7417 // are not considered.
7418 if (ParamsAC.empty())
7419 return false;
7420 Template->getAssociatedConstraints(TemplateAC);
7421 bool IsParamAtLeastAsConstrained;
7422 if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC,
7423 IsParamAtLeastAsConstrained))
7424 return true;
7425 if (!IsParamAtLeastAsConstrained) {
7426 Diag(Arg.getLocation(),
7427 diag::err_template_template_parameter_not_at_least_as_constrained)
7428 << Template << Param << Arg.getSourceRange();
7429 Diag(Param->getLocation(), diag::note_entity_declared_at) << Param;
7430 Diag(Template->getLocation(), diag::note_entity_declared_at)
7431 << Template;
7432 MaybeEmitAmbiguousAtomicConstraintsDiagnostic(Param, ParamsAC, Template,
7433 TemplateAC);
7434 return true;
7435 }
7436 return false;
7437 }
7438 // FIXME: Produce better diagnostics for deduction failures.
7439 }
7440
7441 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
7442 Params,
7443 true,
7444 TPL_TemplateTemplateArgumentMatch,
7445 Arg.getLocation());
7446}
7447
7448/// Given a non-type template argument that refers to a
7449/// declaration and the type of its corresponding non-type template
7450/// parameter, produce an expression that properly refers to that
7451/// declaration.
7452ExprResult
7453Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
7454 QualType ParamType,
7455 SourceLocation Loc) {
7456 // C++ [temp.param]p8:
7457 //
7458 // A non-type template-parameter of type "array of T" or
7459 // "function returning T" is adjusted to be of type "pointer to
7460 // T" or "pointer to function returning T", respectively.
7461 if (ParamType->isArrayType())
7462 ParamType = Context.getArrayDecayedType(ParamType);
7463 else if (ParamType->isFunctionType())
7464 ParamType = Context.getPointerType(ParamType);
7465
7466 // For a NULL non-type template argument, return nullptr casted to the
7467 // parameter's type.
7468 if (Arg.getKind() == TemplateArgument::NullPtr) {
7469 return ImpCastExprToType(
7470 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
7471 ParamType,
7472 ParamType->getAs<MemberPointerType>()
7473 ? CK_NullToMemberPointer
7474 : CK_NullToPointer);
7475 }
7476 assert(Arg.getKind() == TemplateArgument::Declaration &&
7477 "Only declaration template arguments permitted here");
7478
7479 ValueDecl *VD = Arg.getAsDecl();
7480
7481 CXXScopeSpec SS;
7482 if (ParamType->isMemberPointerType()) {
7483 // If this is a pointer to member, we need to use a qualified name to
7484 // form a suitable pointer-to-member constant.
7485 assert(VD->getDeclContext()->isRecord() &&
7486 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
7487 isa<IndirectFieldDecl>(VD)));
7488 QualType ClassType
7489 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
7490 NestedNameSpecifier *Qualifier
7491 = NestedNameSpecifier::Create(Context, nullptr, false,
7492 ClassType.getTypePtr());
7493 SS.MakeTrivial(Context, Qualifier, Loc);
7494 }
7495
7496 ExprResult RefExpr = BuildDeclarationNameExpr(
7497 SS, DeclarationNameInfo(VD->getDeclName(), Loc), VD);
7498 if (RefExpr.isInvalid())
7499 return ExprError();
7500
7501 // For a pointer, the argument declaration is the pointee. Take its address.
7502 QualType ElemT(RefExpr.get()->getType()->getArrayElementTypeNoTypeQual(), 0);
7503 if (ParamType->isPointerType() && !ElemT.isNull() &&
7504 Context.hasSimilarType(ElemT, ParamType->getPointeeType())) {
7505 // Decay an array argument if we want a pointer to its first element.
7506 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7507 if (RefExpr.isInvalid())
7508 return ExprError();
7509 } else if (ParamType->isPointerType() || ParamType->isMemberPointerType()) {
7510 // For any other pointer, take the address (or form a pointer-to-member).
7511 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7512 if (RefExpr.isInvalid())
7513 return ExprError();
7514 } else if (ParamType->isRecordType()) {
7515 assert(isa<TemplateParamObjectDecl>(VD) &&
7516 "arg for class template param not a template parameter object");
7517 // No conversions apply in this case.
7518 return RefExpr;
7519 } else {
7520 assert(ParamType->isReferenceType() &&
7521 "unexpected type for decl template argument");
7522 }
7523
7524 // At this point we should have the right value category.
7525 assert(ParamType->isReferenceType() == RefExpr.get()->isLValue() &&
7526 "value kind mismatch for non-type template argument");
7527
7528 // The type of the template parameter can differ from the type of the
7529 // argument in various ways; convert it now if necessary.
7530 QualType DestExprType = ParamType.getNonLValueExprType(Context);
7531 if (!Context.hasSameType(RefExpr.get()->getType(), DestExprType)) {
7532 CastKind CK;
7533 QualType Ignored;
7534 if (Context.hasSimilarType(RefExpr.get()->getType(), DestExprType) ||
7535 IsFunctionConversion(RefExpr.get()->getType(), DestExprType, Ignored)) {
7536 CK = CK_NoOp;
7537 } else if (ParamType->isVoidPointerType() &&
7538 RefExpr.get()->getType()->isPointerType()) {
7539 CK = CK_BitCast;
7540 } else {
7541 // FIXME: Pointers to members can need conversion derived-to-base or
7542 // base-to-derived conversions. We currently don't retain enough
7543 // information to convert properly (we need to track a cast path or
7544 // subobject number in the template argument).
7545 llvm_unreachable(
7546 "unexpected conversion required for non-type template argument");
7547 }
7548 RefExpr = ImpCastExprToType(RefExpr.get(), DestExprType, CK,
7549 RefExpr.get()->getValueKind());
7550 }
7551
7552 return RefExpr;
7553}
7554
7555/// Construct a new expression that refers to the given
7556/// integral template argument with the given source-location
7557/// information.
7558///
7559/// This routine takes care of the mapping from an integral template
7560/// argument (which may have any integral type) to the appropriate
7561/// literal value.
7562ExprResult
7563Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7564 SourceLocation Loc) {
7565 assert(Arg.getKind() == TemplateArgument::Integral &&
7566 "Operation is only valid for integral template arguments");
7567 QualType OrigT = Arg.getIntegralType();
7568
7569 // If this is an enum type that we're instantiating, we need to use an integer
7570 // type the same size as the enumerator. We don't want to build an
7571 // IntegerLiteral with enum type. The integer type of an enum type can be of
7572 // any integral type with C++11 enum classes, make sure we create the right
7573 // type of literal for it.
7574 QualType T = OrigT;
7575 if (const EnumType *ET = OrigT->getAs<EnumType>())
7576 T = ET->getDecl()->getIntegerType();
7577
7578 Expr *E;
7579 if (T->isAnyCharacterType()) {
7580 CharacterLiteral::CharacterKind Kind;
7581 if (T->isWideCharType())
7582 Kind = CharacterLiteral::Wide;
7583 else if (T->isChar8Type() && getLangOpts().Char8)
7584 Kind = CharacterLiteral::UTF8;
7585 else if (T->isChar16Type())
7586 Kind = CharacterLiteral::UTF16;
7587 else if (T->isChar32Type())
7588 Kind = CharacterLiteral::UTF32;
7589 else
7590 Kind = CharacterLiteral::Ascii;
7591
7592 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7593 Kind, T, Loc);
7594 } else if (T->isBooleanType()) {
7595 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7596 T, Loc);
7597 } else if (T->isNullPtrType()) {
7598 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7599 } else {
7600 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7601 }
7602
7603 if (OrigT->isEnumeralType()) {
7604 // FIXME: This is a hack. We need a better way to handle substituted
7605 // non-type template parameters.
7606 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7607 nullptr, CurFPFeatureOverrides(),
7608 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7609 Loc, Loc);
7610 }
7611
7612 return E;
7613}
7614
7615/// Match two template parameters within template parameter lists.
7616static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7617 bool Complain,
7618 Sema::TemplateParameterListEqualKind Kind,
7619 SourceLocation TemplateArgLoc) {
7620 // Check the actual kind (type, non-type, template).
7621 if (Old->getKind() != New->getKind()) {
7622 if (Complain) {
7623 unsigned NextDiag = diag::err_template_param_different_kind;
7624 if (TemplateArgLoc.isValid()) {
7625 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7626 NextDiag = diag::note_template_param_different_kind;
7627 }
7628 S.Diag(New->getLocation(), NextDiag)
7629 << (Kind != Sema::TPL_TemplateMatch);
7630 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7631 << (Kind != Sema::TPL_TemplateMatch);
7632 }
7633
7634 return false;
7635 }
7636
7637 // Check that both are parameter packs or neither are parameter packs.
7638 // However, if we are matching a template template argument to a
7639 // template template parameter, the template template parameter can have
7640 // a parameter pack where the template template argument does not.
7641 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7642 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7643 Old->isTemplateParameterPack())) {
7644 if (Complain) {
7645 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7646 if (TemplateArgLoc.isValid()) {
7647 S.Diag(TemplateArgLoc,
7648 diag::err_template_arg_template_params_mismatch);
7649 NextDiag = diag::note_template_parameter_pack_non_pack;
7650 }
7651
7652 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7653 : isa<NonTypeTemplateParmDecl>(New)? 1
7654 : 2;
7655 S.Diag(New->getLocation(), NextDiag)
7656 << ParamKind << New->isParameterPack();
7657 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7658 << ParamKind << Old->isParameterPack();
7659 }
7660
7661 return false;
7662 }
7663
7664 // For non-type template parameters, check the type of the parameter.
7665 if (NonTypeTemplateParmDecl *OldNTTP
7666 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7667 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7668
7669 // If we are matching a template template argument to a template
7670 // template parameter and one of the non-type template parameter types
7671 // is dependent, then we must wait until template instantiation time
7672 // to actually compare the arguments.
7673 if (Kind != Sema::TPL_TemplateTemplateArgumentMatch ||
7674 (!OldNTTP->getType()->isDependentType() &&
7675 !NewNTTP->getType()->isDependentType()))
7676 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7677 if (Complain) {
7678 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7679 if (TemplateArgLoc.isValid()) {
7680 S.Diag(TemplateArgLoc,
7681 diag::err_template_arg_template_params_mismatch);
7682 NextDiag = diag::note_template_nontype_parm_different_type;
7683 }
7684 S.Diag(NewNTTP->getLocation(), NextDiag)
7685 << NewNTTP->getType()
7686 << (Kind != Sema::TPL_TemplateMatch);
7687 S.Diag(OldNTTP->getLocation(),
7688 diag::note_template_nontype_parm_prev_declaration)
7689 << OldNTTP->getType();
7690 }
7691
7692 return false;
7693 }
7694 }
7695 // For template template parameters, check the template parameter types.
7696 // The template parameter lists of template template
7697 // parameters must agree.
7698 else if (TemplateTemplateParmDecl *OldTTP
7699 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7700 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7701 if (!S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7702 OldTTP->getTemplateParameters(),
7703 Complain,
7704 (Kind == Sema::TPL_TemplateMatch
7705 ? Sema::TPL_TemplateTemplateParmMatch
7706 : Kind),
7707 TemplateArgLoc))
7708 return false;
7709 } else if (Kind != Sema::TPL_TemplateTemplateArgumentMatch) {
7710 const Expr *NewC = nullptr, *OldC = nullptr;
7711 if (const auto *TC = cast<TemplateTypeParmDecl>(New)->getTypeConstraint())
7712 NewC = TC->getImmediatelyDeclaredConstraint();
7713 if (const auto *TC = cast<TemplateTypeParmDecl>(Old)->getTypeConstraint())
7714 OldC = TC->getImmediatelyDeclaredConstraint();
7715
7716 auto Diagnose = [&] {
7717 S.Diag(NewC ? NewC->getBeginLoc() : New->getBeginLoc(),
7718 diag::err_template_different_type_constraint);
7719 S.Diag(OldC ? OldC->getBeginLoc() : Old->getBeginLoc(),
7720 diag::note_template_prev_declaration) << /*declaration*/0;
7721 };
7722
7723 if (!NewC != !OldC) {
7724 if (Complain)
7725 Diagnose();
7726 return false;
7727 }
7728
7729 if (NewC) {
7730 llvm::FoldingSetNodeID OldCID, NewCID;
7731 OldC->Profile(OldCID, S.Context, /*Canonical=*/true);
7732 NewC->Profile(NewCID, S.Context, /*Canonical=*/true);
7733 if (OldCID != NewCID) {
7734 if (Complain)
7735 Diagnose();
7736 return false;
7737 }
7738 }
7739 }
7740
7741 return true;
7742}
7743
7744/// Diagnose a known arity mismatch when comparing template argument
7745/// lists.
7746static
7747void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7748 TemplateParameterList *New,
7749 TemplateParameterList *Old,
7750 Sema::TemplateParameterListEqualKind Kind,
7751 SourceLocation TemplateArgLoc) {
7752 unsigned NextDiag = diag::err_template_param_list_different_arity;
7753 if (TemplateArgLoc.isValid()) {
7754 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7755 NextDiag = diag::note_template_param_list_different_arity;
7756 }
7757 S.Diag(New->getTemplateLoc(), NextDiag)
7758 << (New->size() > Old->size())
7759 << (Kind != Sema::TPL_TemplateMatch)
7760 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7761 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7762 << (Kind != Sema::TPL_TemplateMatch)
7763 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7764}
7765
7766/// Determine whether the given template parameter lists are
7767/// equivalent.
7768///
7769/// \param New The new template parameter list, typically written in the
7770/// source code as part of a new template declaration.
7771///
7772/// \param Old The old template parameter list, typically found via
7773/// name lookup of the template declared with this template parameter
7774/// list.
7775///
7776/// \param Complain If true, this routine will produce a diagnostic if
7777/// the template parameter lists are not equivalent.
7778///
7779/// \param Kind describes how we are to match the template parameter lists.
7780///
7781/// \param TemplateArgLoc If this source location is valid, then we
7782/// are actually checking the template parameter list of a template
7783/// argument (New) against the template parameter list of its
7784/// corresponding template template parameter (Old). We produce
7785/// slightly different diagnostics in this scenario.
7786///
7787/// \returns True if the template parameter lists are equal, false
7788/// otherwise.
7789bool
7790Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7791 TemplateParameterList *Old,
7792 bool Complain,
7793 TemplateParameterListEqualKind Kind,
7794 SourceLocation TemplateArgLoc) {
7795 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7796 if (Complain)
7797 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7798 TemplateArgLoc);
7799
7800 return false;
7801 }
7802
7803 // C++0x [temp.arg.template]p3:
7804 // A template-argument matches a template template-parameter (call it P)
7805 // when each of the template parameters in the template-parameter-list of
7806 // the template-argument's corresponding class template or alias template
7807 // (call it A) matches the corresponding template parameter in the
7808 // template-parameter-list of P. [...]
7809 TemplateParameterList::iterator NewParm = New->begin();
7810 TemplateParameterList::iterator NewParmEnd = New->end();
7811 for (TemplateParameterList::iterator OldParm = Old->begin(),
7812 OldParmEnd = Old->end();
7813 OldParm != OldParmEnd; ++OldParm) {
7814 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7815 !(*OldParm)->isTemplateParameterPack()) {
7816 if (NewParm == NewParmEnd) {
7817 if (Complain)
7818 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7819 TemplateArgLoc);
7820
7821 return false;
7822 }
7823
7824 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7825 Kind, TemplateArgLoc))
7826 return false;
7827
7828 ++NewParm;
7829 continue;
7830 }
7831
7832 // C++0x [temp.arg.template]p3:
7833 // [...] When P's template- parameter-list contains a template parameter
7834 // pack (14.5.3), the template parameter pack will match zero or more
7835 // template parameters or template parameter packs in the
7836 // template-parameter-list of A with the same type and form as the
7837 // template parameter pack in P (ignoring whether those template
7838 // parameters are template parameter packs).
7839 for (; NewParm != NewParmEnd; ++NewParm) {
7840 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7841 Kind, TemplateArgLoc))
7842 return false;
7843 }
7844 }
7845
7846 // Make sure we exhausted all of the arguments.
7847 if (NewParm != NewParmEnd) {
7848 if (Complain)
7849 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7850 TemplateArgLoc);
7851
7852 return false;
7853 }
7854
7855 if (Kind != TPL_TemplateTemplateArgumentMatch) {
7856 const Expr *NewRC = New->getRequiresClause();
7857 const Expr *OldRC = Old->getRequiresClause();
7858
7859 auto Diagnose = [&] {
7860 Diag(NewRC ? NewRC->getBeginLoc() : New->getTemplateLoc(),
7861 diag::err_template_different_requires_clause);
7862 Diag(OldRC ? OldRC->getBeginLoc() : Old->getTemplateLoc(),
7863 diag::note_template_prev_declaration) << /*declaration*/0;
7864 };
7865
7866 if (!NewRC != !OldRC) {
7867 if (Complain)
7868 Diagnose();
7869 return false;
7870 }
7871
7872 if (NewRC) {
7873 llvm::FoldingSetNodeID OldRCID, NewRCID;
7874 OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
7875 NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
7876 if (OldRCID != NewRCID) {
7877 if (Complain)
7878 Diagnose();
7879 return false;
7880 }
7881 }
7882 }
7883
7884 return true;
7885}
7886
7887/// Check whether a template can be declared within this scope.
7888///
7889/// If the template declaration is valid in this scope, returns
7890/// false. Otherwise, issues a diagnostic and returns true.
7891bool
7892Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7893 if (!S)
7894 return false;
7895
7896 // Find the nearest enclosing declaration scope.
7897 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7898 (S->getFlags() & Scope::TemplateParamScope) != 0)
7899 S = S->getParent();
7900
7901 // C++ [temp.pre]p6: [P2096]
7902 // A template, explicit specialization, or partial specialization shall not
7903 // have C linkage.
7904 DeclContext *Ctx = S->getEntity();
7905 if (Ctx && Ctx->isExternCContext()) {
7906 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7907 << TemplateParams->getSourceRange();
7908 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7909 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7910 return true;
7911 }
7912 Ctx = Ctx ? Ctx->getRedeclContext() : nullptr;
7913
7914 // C++ [temp]p2:
7915 // A template-declaration can appear only as a namespace scope or
7916 // class scope declaration.
7917 // C++ [temp.expl.spec]p3:
7918 // An explicit specialization may be declared in any scope in which the
7919 // corresponding primary template may be defined.
7920 // C++ [temp.class.spec]p6: [P2096]
7921 // A partial specialization may be declared in any scope in which the
7922 // corresponding primary template may be defined.
7923 if (Ctx) {
7924 if (Ctx->isFileContext())
7925 return false;
7926 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7927 // C++ [temp.mem]p2:
7928 // A local class shall not have member templates.
7929 if (RD->isLocalClass())
7930 return Diag(TemplateParams->getTemplateLoc(),
7931 diag::err_template_inside_local_class)
7932 << TemplateParams->getSourceRange();
7933 else
7934 return false;
7935 }
7936 }
7937
7938 return Diag(TemplateParams->getTemplateLoc(),
7939 diag::err_template_outside_namespace_or_class_scope)
7940 << TemplateParams->getSourceRange();
7941}
7942
7943/// Determine what kind of template specialization the given declaration
7944/// is.
7945static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7946 if (!D)
7947 return TSK_Undeclared;
7948
7949 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7950 return Record->getTemplateSpecializationKind();
7951 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7952 return Function->getTemplateSpecializationKind();
7953 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7954 return Var->getTemplateSpecializationKind();
7955
7956 return TSK_Undeclared;
7957}
7958
7959/// Check whether a specialization is well-formed in the current
7960/// context.
7961///
7962/// This routine determines whether a template specialization can be declared
7963/// in the current context (C++ [temp.expl.spec]p2).
7964///
7965/// \param S the semantic analysis object for which this check is being
7966/// performed.
7967///
7968/// \param Specialized the entity being specialized or instantiated, which
7969/// may be a kind of template (class template, function template, etc.) or
7970/// a member of a class template (member function, static data member,
7971/// member class).
7972///
7973/// \param PrevDecl the previous declaration of this entity, if any.
7974///
7975/// \param Loc the location of the explicit specialization or instantiation of
7976/// this entity.
7977///
7978/// \param IsPartialSpecialization whether this is a partial specialization of
7979/// a class template.
7980///
7981/// \returns true if there was an error that we cannot recover from, false
7982/// otherwise.
7983static bool CheckTemplateSpecializationScope(Sema &S,
7984 NamedDecl *Specialized,
7985 NamedDecl *PrevDecl,
7986 SourceLocation Loc,
7987 bool IsPartialSpecialization) {
7988 // Keep these "kind" numbers in sync with the %select statements in the
7989 // various diagnostics emitted by this routine.
7990 int EntityKind = 0;
7991 if (isa<ClassTemplateDecl>(Specialized))
7992 EntityKind = IsPartialSpecialization? 1 : 0;
7993 else if (isa<VarTemplateDecl>(Specialized))
7994 EntityKind = IsPartialSpecialization ? 3 : 2;
7995 else if (isa<FunctionTemplateDecl>(Specialized))
7996 EntityKind = 4;
7997 else if (isa<CXXMethodDecl>(Specialized))
7998 EntityKind = 5;
7999 else if (isa<VarDecl>(Specialized))
8000 EntityKind = 6;
8001 else if (isa<RecordDecl>(Specialized))
8002 EntityKind = 7;
8003 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
8004 EntityKind = 8;
8005 else {
8006 S.Diag(Loc, diag::err_template_spec_unknown_kind)
8007 << S.getLangOpts().CPlusPlus11;
8008 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8009 return true;
8010 }
8011
8012 // C++ [temp.expl.spec]p2:
8013 // An explicit specialization may be declared in any scope in which
8014 // the corresponding primary template may be defined.
8015 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
8016 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
8017 << Specialized;
8018 return true;
8019 }
8020
8021 // C++ [temp.class.spec]p6:
8022 // A class template partial specialization may be declared in any
8023 // scope in which the primary template may be defined.
8024 DeclContext *SpecializedContext =
8025 Specialized->getDeclContext()->getRedeclContext();
8026 DeclContext *DC = S.CurContext->getRedeclContext();
8027
8028 // Make sure that this redeclaration (or definition) occurs in the same
8029 // scope or an enclosing namespace.
8030 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
8031 : DC->Equals(SpecializedContext))) {
8032 if (isa<TranslationUnitDecl>(SpecializedContext))
8033 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
8034 << EntityKind << Specialized;
8035 else {
8036 auto *ND = cast<NamedDecl>(SpecializedContext);
8037 int Diag = diag::err_template_spec_redecl_out_of_scope;
8038 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
8039 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
8040 S.Diag(Loc, Diag) << EntityKind << Specialized
8041 << ND << isa<CXXRecordDecl>(ND);
8042 }
8043
8044 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
8045
8046 // Don't allow specializing in the wrong class during error recovery.
8047 // Otherwise, things can go horribly wrong.
8048 if (DC->isRecord())
8049 return true;
8050 }
8051
8052 return false;
8053}
8054
8055static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
8056 if (!E->isTypeDependent())
8057 return SourceLocation();
8058 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8059 Checker.TraverseStmt(E);
8060 if (Checker.MatchLoc.isInvalid())
8061 return E->getSourceRange();
8062 return Checker.MatchLoc;
8063}
8064
8065static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
8066 if (!TL.getType()->isDependentType())
8067 return SourceLocation();
8068 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
8069 Checker.TraverseTypeLoc(TL);
8070 if (Checker.MatchLoc.isInvalid())
8071 return TL.getSourceRange();
8072 return Checker.MatchLoc;
8073}
8074
8075/// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
8076/// that checks non-type template partial specialization arguments.
8077static bool CheckNonTypeTemplatePartialSpecializationArgs(
8078 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
8079 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
8080 for (unsigned I = 0; I != NumArgs; ++I) {
8081 if (Args[I].getKind() == TemplateArgument::Pack) {
8082 if (CheckNonTypeTemplatePartialSpecializationArgs(
8083 S, TemplateNameLoc, Param, Args[I].pack_begin(),
8084 Args[I].pack_size(), IsDefaultArgument))
8085 return true;
8086
8087 continue;
8088 }
8089
8090 if (Args[I].getKind() != TemplateArgument::Expression)
8091 continue;
8092
8093 Expr *ArgExpr = Args[I].getAsExpr();
8094
8095 // We can have a pack expansion of any of the bullets below.
8096 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
8097 ArgExpr = Expansion->getPattern();
8098
8099 // Strip off any implicit casts we added as part of type checking.
8100 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
8101 ArgExpr = ICE->getSubExpr();
8102
8103 // C++ [temp.class.spec]p8:
8104 // A non-type argument is non-specialized if it is the name of a
8105 // non-type parameter. All other non-type arguments are
8106 // specialized.
8107 //
8108 // Below, we check the two conditions that only apply to
8109 // specialized non-type arguments, so skip any non-specialized
8110 // arguments.
8111 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
8112 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
8113 continue;
8114
8115 // C++ [temp.class.spec]p9:
8116 // Within the argument list of a class template partial
8117 // specialization, the following restrictions apply:
8118 // -- A partially specialized non-type argument expression
8119 // shall not involve a template parameter of the partial
8120 // specialization except when the argument expression is a
8121 // simple identifier.
8122 // -- The type of a template parameter corresponding to a
8123 // specialized non-type argument shall not be dependent on a
8124 // parameter of the specialization.
8125 // DR1315 removes the first bullet, leaving an incoherent set of rules.
8126 // We implement a compromise between the original rules and DR1315:
8127 // -- A specialized non-type template argument shall not be
8128 // type-dependent and the corresponding template parameter
8129 // shall have a non-dependent type.
8130 SourceRange ParamUseRange =
8131 findTemplateParameterInType(Param->getDepth(), ArgExpr);
8132 if (ParamUseRange.isValid()) {
8133 if (IsDefaultArgument) {
8134 S.Diag(TemplateNameLoc,
8135 diag::err_dependent_non_type_arg_in_partial_spec);
8136 S.Diag(ParamUseRange.getBegin(),
8137 diag::note_dependent_non_type_default_arg_in_partial_spec)
8138 << ParamUseRange;
8139 } else {
8140 S.Diag(ParamUseRange.getBegin(),
8141 diag::err_dependent_non_type_arg_in_partial_spec)
8142 << ParamUseRange;
8143 }
8144 return true;
8145 }
8146
8147 ParamUseRange = findTemplateParameter(
8148 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
8149 if (ParamUseRange.isValid()) {
8150 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
8151 diag::err_dependent_typed_non_type_arg_in_partial_spec)
8152 << Param->getType();
8153 S.Diag(Param->getLocation(), diag::note_template_param_here)
8154 << (IsDefaultArgument ? ParamUseRange : SourceRange())
8155 << ParamUseRange;
8156 return true;
8157 }
8158 }
8159
8160 return false;
8161}
8162
8163/// Check the non-type template arguments of a class template
8164/// partial specialization according to C++ [temp.class.spec]p9.
8165///
8166/// \param TemplateNameLoc the location of the template name.
8167/// \param PrimaryTemplate the template parameters of the primary class
8168/// template.
8169/// \param NumExplicit the number of explicitly-specified template arguments.
8170/// \param TemplateArgs the template arguments of the class template
8171/// partial specialization.
8172///
8173/// \returns \c true if there was an error, \c false otherwise.
8174bool Sema::CheckTemplatePartialSpecializationArgs(
8175 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
8176 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
8177 // We have to be conservative when checking a template in a dependent
8178 // context.
8179 if (PrimaryTemplate->getDeclContext()->isDependentContext())
8180 return false;
8181
8182 TemplateParameterList *TemplateParams =
8183 PrimaryTemplate->getTemplateParameters();
8184 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8185 NonTypeTemplateParmDecl *Param
8186 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
8187 if (!Param)
8188 continue;
8189
8190 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
8191 Param, &TemplateArgs[I],
8192 1, I >= NumExplicit))
8193 return true;
8194 }
8195
8196 return false;
8197}
8198
8199DeclResult Sema::ActOnClassTemplateSpecialization(
8200 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
8201 SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
8202 TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
8203 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
8204 assert(TUK != TUK_Reference && "References are not specializations");
8205
8206 // NOTE: KWLoc is the location of the tag keyword. This will instead
8207 // store the location of the outermost template keyword in the declaration.
8208 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
8209 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
8210 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
8211 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
8212 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
8213
8214 // Find the class template we're specializing
8215 TemplateName Name = TemplateId.Template.get();
8216 ClassTemplateDecl *ClassTemplate
8217 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
8218
8219 if (!ClassTemplate) {
8220 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
8221 << (Name.getAsTemplateDecl() &&
8222 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
8223 return true;
8224 }
8225
8226 bool isMemberSpecialization = false;
8227 bool isPartialSpecialization = false;
8228
8229 // Check the validity of the template headers that introduce this
8230 // template.
8231 // FIXME: We probably shouldn't complain about these headers for
8232 // friend declarations.
8233 bool Invalid = false;
8234 TemplateParameterList *TemplateParams =
8235 MatchTemplateParametersToScopeSpecifier(
8236 KWLoc, TemplateNameLoc, SS, &TemplateId,
8237 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
8238 Invalid);
8239 if (Invalid)
8240 return true;
8241
8242 // Check that we can declare a template specialization here.
8243 if (TemplateParams && CheckTemplateDeclScope(S, TemplateParams))
8244 return true;
8245
8246 if (TemplateParams && TemplateParams->size() > 0) {
8247 isPartialSpecialization = true;
8248
8249 if (TUK == TUK_Friend) {
8250 Diag(KWLoc, diag::err_partial_specialization_friend)
8251 << SourceRange(LAngleLoc, RAngleLoc);
8252 return true;
8253 }
8254
8255 // C++ [temp.class.spec]p10:
8256 // The template parameter list of a specialization shall not
8257 // contain default template argument values.
8258 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
8259 Decl *Param = TemplateParams->getParam(I);
8260 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
8261 if (TTP->hasDefaultArgument()) {
8262 Diag(TTP->getDefaultArgumentLoc(),
8263 diag::err_default_arg_in_partial_spec);
8264 TTP->removeDefaultArgument();
8265 }
8266 } else if (NonTypeTemplateParmDecl *NTTP
8267 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
8268 if (Expr *DefArg = NTTP->getDefaultArgument()) {
8269 Diag(NTTP->getDefaultArgumentLoc(),
8270 diag::err_default_arg_in_partial_spec)
8271 << DefArg->getSourceRange();
8272 NTTP->removeDefaultArgument();
8273 }
8274 } else {
8275 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
8276 if (TTP->hasDefaultArgument()) {
8277 Diag(TTP->getDefaultArgument().getLocation(),
8278 diag::err_default_arg_in_partial_spec)
8279 << TTP->getDefaultArgument().getSourceRange();
8280 TTP->removeDefaultArgument();
8281 }
8282 }
8283 }
8284 } else if (TemplateParams) {
8285 if (TUK == TUK_Friend)
8286 Diag(KWLoc, diag::err_template_spec_friend)
8287 << FixItHint::CreateRemoval(
8288 SourceRange(TemplateParams->getTemplateLoc(),
8289 TemplateParams->getRAngleLoc()))
8290 << SourceRange(LAngleLoc, RAngleLoc);
8291 } else {
8292 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
8293 }
8294
8295 // Check that the specialization uses the same tag kind as the
8296 // original template.
8297 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8298 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
8299 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8300 Kind, TUK == TUK_Definition, KWLoc,
8301 ClassTemplate->getIdentifier())) {
8302 Diag(KWLoc, diag::err_use_with_wrong_tag)
8303 << ClassTemplate
8304 << FixItHint::CreateReplacement(KWLoc,
8305 ClassTemplate->getTemplatedDecl()->getKindName());
8306 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8307 diag::note_previous_use);
8308 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8309 }
8310
8311 // Translate the parser's template argument list in our AST format.
8312 TemplateArgumentListInfo TemplateArgs =
8313 makeTemplateArgumentListInfo(*this, TemplateId);
8314
8315 // Check for unexpanded parameter packs in any of the template arguments.
8316 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
8317 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
8318 UPPC_PartialSpecialization))
8319 return true;
8320
8321 // Check that the template argument list is well-formed for this
8322 // template.
8323 SmallVector<TemplateArgument, 4> Converted;
8324 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
8325 TemplateArgs, false, Converted,
8326 /*UpdateArgsWithConversion=*/true))
8327 return true;
8328
8329 // Find the class template (partial) specialization declaration that
8330 // corresponds to these arguments.
8331 if (isPartialSpecialization) {
8332 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
8333 TemplateArgs.size(), Converted))
8334 return true;
8335
8336 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
8337 // also do it during instantiation.
8338 if (!Name.isDependent() &&
8339 !TemplateSpecializationType::anyDependentTemplateArguments(TemplateArgs,
8340 Converted)) {
8341 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
8342 << ClassTemplate->getDeclName();
8343 isPartialSpecialization = false;
8344 }
8345 }
8346
8347 void *InsertPos = nullptr;
8348 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
8349
8350 if (isPartialSpecialization)
8351 PrevDecl = ClassTemplate->findPartialSpecialization(Converted,
8352 TemplateParams,
8353 InsertPos);
8354 else
8355 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
8356
8357 ClassTemplateSpecializationDecl *Specialization = nullptr;
8358
8359 // Check whether we can declare a class template specialization in
8360 // the current scope.
8361 if (TUK != TUK_Friend &&
8362 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
8363 TemplateNameLoc,
8364 isPartialSpecialization))
8365 return true;
8366
8367 // The canonical type
8368 QualType CanonType;
8369 if (isPartialSpecialization) {
8370 // Build the canonical type that describes the converted template
8371 // arguments of the class template partial specialization.
8372 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8373 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
8374 Converted);
8375
8376 if (Context.hasSameType(CanonType,
8377 ClassTemplate->getInjectedClassNameSpecialization()) &&
8378 (!Context.getLangOpts().CPlusPlus20 ||
8379 !TemplateParams->hasAssociatedConstraints())) {
8380 // C++ [temp.class.spec]p9b3:
8381 //
8382 // -- The argument list of the specialization shall not be identical
8383 // to the implicit argument list of the primary template.
8384 //
8385 // This rule has since been removed, because it's redundant given DR1495,
8386 // but we keep it because it produces better diagnostics and recovery.
8387 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
8388 << /*class template*/0 << (TUK == TUK_Definition)
8389 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
8390 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
8391 ClassTemplate->getIdentifier(),
8392 TemplateNameLoc,
8393 Attr,
8394 TemplateParams,
8395 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
8396 /*FriendLoc*/SourceLocation(),
8397 TemplateParameterLists.size() - 1,
8398 TemplateParameterLists.data());
8399 }
8400
8401 // Create a new class template partial specialization declaration node.
8402 ClassTemplatePartialSpecializationDecl *PrevPartial
8403 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
8404 ClassTemplatePartialSpecializationDecl *Partial
8405 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
8406 ClassTemplate->getDeclContext(),
8407 KWLoc, TemplateNameLoc,
8408 TemplateParams,
8409 ClassTemplate,
8410 Converted,
8411 TemplateArgs,
8412 CanonType,
8413 PrevPartial);
8414 SetNestedNameSpecifier(*this, Partial, SS);
8415 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
8416 Partial->setTemplateParameterListsInfo(
8417 Context, TemplateParameterLists.drop_back(1));
8418 }
8419
8420 if (!PrevPartial)
8421 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
8422 Specialization = Partial;
8423
8424 // If we are providing an explicit specialization of a member class
8425 // template specialization, make a note of that.
8426 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
8427 PrevPartial->setMemberSpecialization();
8428
8429 CheckTemplatePartialSpecialization(Partial);
8430 } else {
8431 // Create a new class template specialization declaration node for
8432 // this explicit specialization or friend declaration.
8433 Specialization
8434 = ClassTemplateSpecializationDecl::Create(Context, Kind,
8435 ClassTemplate->getDeclContext(),
8436 KWLoc, TemplateNameLoc,
8437 ClassTemplate,
8438 Converted,
8439 PrevDecl);
8440 SetNestedNameSpecifier(*this, Specialization, SS);
8441 if (TemplateParameterLists.size() > 0) {
8442 Specialization->setTemplateParameterListsInfo(Context,
8443 TemplateParameterLists);
8444 }
8445
8446 if (!PrevDecl)
8447 ClassTemplate->AddSpecialization(Specialization, InsertPos);
8448
8449 if (CurContext->isDependentContext()) {
8450 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
8451 CanonType = Context.getTemplateSpecializationType(
8452 CanonTemplate, Converted);
8453 } else {
8454 CanonType = Context.getTypeDeclType(Specialization);
8455 }
8456 }
8457
8458 // C++ [temp.expl.spec]p6:
8459 // If a template, a member template or the member of a class template is
8460 // explicitly specialized then that specialization shall be declared
8461 // before the first use of that specialization that would cause an implicit
8462 // instantiation to take place, in every translation unit in which such a
8463 // use occurs; no diagnostic is required.
8464 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
8465 bool Okay = false;
8466 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8467 // Is there any previous explicit specialization declaration?
8468 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8469 Okay = true;
8470 break;
8471 }
8472 }
8473
8474 if (!Okay) {
8475 SourceRange Range(TemplateNameLoc, RAngleLoc);
8476 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
8477 << Context.getTypeDeclType(Specialization) << Range;
8478
8479 Diag(PrevDecl->getPointOfInstantiation(),
8480 diag::note_instantiation_required_here)
8481 << (PrevDecl->getTemplateSpecializationKind()
8482 != TSK_ImplicitInstantiation);
8483 return true;
8484 }
8485 }
8486
8487 // If this is not a friend, note that this is an explicit specialization.
8488 if (TUK != TUK_Friend)
8489 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
8490
8491 // Check that this isn't a redefinition of this specialization.
8492 if (TUK == TUK_Definition) {
8493 RecordDecl *Def = Specialization->getDefinition();
8494 NamedDecl *Hidden = nullptr;
8495 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
8496 SkipBody->ShouldSkip = true;
8497 SkipBody->Previous = Def;
8498 makeMergedDefinitionVisible(Hidden);
8499 } else if (Def) {
8500 SourceRange Range(TemplateNameLoc, RAngleLoc);
8501 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
8502 Diag(Def->getLocation(), diag::note_previous_definition);
8503 Specialization->setInvalidDecl();
8504 return true;
8505 }
8506 }
8507
8508 ProcessDeclAttributeList(S, Specialization, Attr);
8509
8510 // Add alignment attributes if necessary; these attributes are checked when
8511 // the ASTContext lays out the structure.
8512 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
8513 AddAlignmentAttributesForRecord(Specialization);
8514 AddMsStructLayoutForRecord(Specialization);
8515 }
8516
8517 if (ModulePrivateLoc.isValid())
8518 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
8519 << (isPartialSpecialization? 1 : 0)
8520 << FixItHint::CreateRemoval(ModulePrivateLoc);
8521
8522 // Build the fully-sugared type for this class template
8523 // specialization as the user wrote in the specialization
8524 // itself. This means that we'll pretty-print the type retrieved
8525 // from the specialization's declaration the way that the user
8526 // actually wrote the specialization, rather than formatting the
8527 // name based on the "canonical" representation used to store the
8528 // template arguments in the specialization.
8529 TypeSourceInfo *WrittenTy
8530 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8531 TemplateArgs, CanonType);
8532 if (TUK != TUK_Friend) {
8533 Specialization->setTypeAsWritten(WrittenTy);
8534 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
8535 }
8536
8537 // C++ [temp.expl.spec]p9:
8538 // A template explicit specialization is in the scope of the
8539 // namespace in which the template was defined.
8540 //
8541 // We actually implement this paragraph where we set the semantic
8542 // context (in the creation of the ClassTemplateSpecializationDecl),
8543 // but we also maintain the lexical context where the actual
8544 // definition occurs.
8545 Specialization->setLexicalDeclContext(CurContext);
8546
8547 // We may be starting the definition of this specialization.
8548 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
8549 Specialization->startDefinition();
8550
8551 if (TUK == TUK_Friend) {
8552 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
8553 TemplateNameLoc,
8554 WrittenTy,
8555 /*FIXME:*/KWLoc);
8556 Friend->setAccess(AS_public);
8557 CurContext->addDecl(Friend);
8558 } else {
8559 // Add the specialization into its lexical context, so that it can
8560 // be seen when iterating through the list of declarations in that
8561 // context. However, specializations are not found by name lookup.
8562 CurContext->addDecl(Specialization);
8563 }
8564
8565 if (SkipBody && SkipBody->ShouldSkip)
8566 return SkipBody->Previous;
8567
8568 return Specialization;
8569}
8570
8571Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8572 MultiTemplateParamsArg TemplateParameterLists,
8573 Declarator &D) {
8574 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8575 ActOnDocumentableDecl(NewDecl);
8576 return NewDecl;
8577}
8578
8579Decl *Sema::ActOnConceptDefinition(Scope *S,
8580 MultiTemplateParamsArg TemplateParameterLists,
8581 IdentifierInfo *Name, SourceLocation NameLoc,
8582 Expr *ConstraintExpr) {
8583 DeclContext *DC = CurContext;
8584
8585 if (!DC->getRedeclContext()->isFileContext()) {
8586 Diag(NameLoc,
8587 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8588 return nullptr;
8589 }
8590
8591 if (TemplateParameterLists.size() > 1) {
8592 Diag(NameLoc, diag::err_concept_extra_headers);
8593 return nullptr;
8594 }
8595
8596 if (TemplateParameterLists.front()->size() == 0) {
8597 Diag(NameLoc, diag::err_concept_no_parameters);
8598 return nullptr;
8599 }
8600
8601 if (DiagnoseUnexpandedParameterPack(ConstraintExpr))
8602 return nullptr;
8603
8604 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8605 TemplateParameterLists.front(),
8606 ConstraintExpr);
8607
8608 if (NewDecl->hasAssociatedConstraints()) {
8609 // C++2a [temp.concept]p4:
8610 // A concept shall not have associated constraints.
8611 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8612 NewDecl->setInvalidDecl();
8613 }
8614
8615 // Check for conflicting previous declaration.
8616 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8617 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8618 ForVisibleRedeclaration);
8619 LookupName(Previous, S);
8620
8621 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8622 /*AllowInlineNamespace*/false);
8623 if (!Previous.empty()) {
8624 auto *Old = Previous.getRepresentativeDecl();
8625 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8626 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8627 Diag(Old->getLocation(), diag::note_previous_definition);
8628 }
8629
8630 ActOnDocumentableDecl(NewDecl);
8631 PushOnScopeChains(NewDecl, S);
8632 return NewDecl;
8633}
8634
8635/// \brief Strips various properties off an implicit instantiation
8636/// that has just been explicitly specialized.
8637static void StripImplicitInstantiation(NamedDecl *D) {
8638 D->dropAttr<DLLImportAttr>();
8639 D->dropAttr<DLLExportAttr>();
8640
8641 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8642 FD->setInlineSpecified(false);
8643}
8644
8645/// Compute the diagnostic location for an explicit instantiation
8646// declaration or definition.
8647static SourceLocation DiagLocForExplicitInstantiation(
8648 NamedDecl* D, SourceLocation PointOfInstantiation) {
8649 // Explicit instantiations following a specialization have no effect and
8650 // hence no PointOfInstantiation. In that case, walk decl backwards
8651 // until a valid name loc is found.
8652 SourceLocation PrevDiagLoc = PointOfInstantiation;
8653 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8654 Prev = Prev->getPreviousDecl()) {
8655 PrevDiagLoc = Prev->getLocation();
8656 }
8657 assert(PrevDiagLoc.isValid() &&
8658 "Explicit instantiation without point of instantiation?");
8659 return PrevDiagLoc;
8660}
8661
8662/// Diagnose cases where we have an explicit template specialization
8663/// before/after an explicit template instantiation, producing diagnostics
8664/// for those cases where they are required and determining whether the
8665/// new specialization/instantiation will have any effect.
8666///
8667/// \param NewLoc the location of the new explicit specialization or
8668/// instantiation.
8669///
8670/// \param NewTSK the kind of the new explicit specialization or instantiation.
8671///
8672/// \param PrevDecl the previous declaration of the entity.
8673///
8674/// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8675///
8676/// \param PrevPointOfInstantiation if valid, indicates where the previus
8677/// declaration was instantiated (either implicitly or explicitly).
8678///
8679/// \param HasNoEffect will be set to true to indicate that the new
8680/// specialization or instantiation has no effect and should be ignored.
8681///
8682/// \returns true if there was an error that should prevent the introduction of
8683/// the new declaration into the AST, false otherwise.
8684bool
8685Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8686 TemplateSpecializationKind NewTSK,
8687 NamedDecl *PrevDecl,
8688 TemplateSpecializationKind PrevTSK,
8689 SourceLocation PrevPointOfInstantiation,
8690 bool &HasNoEffect) {
8691 HasNoEffect = false;
8692
8693 switch (NewTSK) {
8694 case TSK_Undeclared:
8695 case TSK_ImplicitInstantiation:
8696 assert(
8697 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8698 "previous declaration must be implicit!");
8699 return false;
8700
8701 case TSK_ExplicitSpecialization:
8702 switch (PrevTSK) {
8703 case TSK_Undeclared:
8704 case TSK_ExplicitSpecialization:
8705 // Okay, we're just specializing something that is either already
8706 // explicitly specialized or has merely been mentioned without any
8707 // instantiation.
8708 return false;
8709
8710 case TSK_ImplicitInstantiation:
8711 if (PrevPointOfInstantiation.isInvalid()) {
8712 // The declaration itself has not actually been instantiated, so it is
8713 // still okay to specialize it.
8714 StripImplicitInstantiation(PrevDecl);
8715 return false;
8716 }
8717 // Fall through
8718 LLVM_FALLTHROUGH;
8719
8720 case TSK_ExplicitInstantiationDeclaration:
8721 case TSK_ExplicitInstantiationDefinition:
8722 assert((PrevTSK == TSK_ImplicitInstantiation ||
8723 PrevPointOfInstantiation.isValid()) &&
8724 "Explicit instantiation without point of instantiation?");
8725
8726 // C++ [temp.expl.spec]p6:
8727 // If a template, a member template or the member of a class template
8728 // is explicitly specialized then that specialization shall be declared
8729 // before the first use of that specialization that would cause an
8730 // implicit instantiation to take place, in every translation unit in
8731 // which such a use occurs; no diagnostic is required.
8732 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8733 // Is there any previous explicit specialization declaration?
8734 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8735 return false;
8736 }
8737
8738 Diag(NewLoc, diag::err_specialization_after_instantiation)
8739 << PrevDecl;
8740 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8741 << (PrevTSK != TSK_ImplicitInstantiation);
8742
8743 return true;
8744 }
8745 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8746
8747 case TSK_ExplicitInstantiationDeclaration:
8748 switch (PrevTSK) {
8749 case TSK_ExplicitInstantiationDeclaration:
8750 // This explicit instantiation declaration is redundant (that's okay).
8751 HasNoEffect = true;
8752 return false;
8753
8754 case TSK_Undeclared:
8755 case TSK_ImplicitInstantiation:
8756 // We're explicitly instantiating something that may have already been
8757 // implicitly instantiated; that's fine.
8758 return false;
8759
8760 case TSK_ExplicitSpecialization:
8761 // C++0x [temp.explicit]p4:
8762 // For a given set of template parameters, if an explicit instantiation
8763 // of a template appears after a declaration of an explicit
8764 // specialization for that template, the explicit instantiation has no
8765 // effect.
8766 HasNoEffect = true;
8767 return false;
8768
8769 case TSK_ExplicitInstantiationDefinition:
8770 // C++0x [temp.explicit]p10:
8771 // If an entity is the subject of both an explicit instantiation
8772 // declaration and an explicit instantiation definition in the same
8773 // translation unit, the definition shall follow the declaration.
8774 Diag(NewLoc,
8775 diag::err_explicit_instantiation_declaration_after_definition);
8776
8777 // Explicit instantiations following a specialization have no effect and
8778 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8779 // until a valid name loc is found.
8780 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8781 diag::note_explicit_instantiation_definition_here);
8782 HasNoEffect = true;
8783 return false;
8784 }
8785 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8786
8787 case TSK_ExplicitInstantiationDefinition:
8788 switch (PrevTSK) {
8789 case TSK_Undeclared:
8790 case TSK_ImplicitInstantiation:
8791 // We're explicitly instantiating something that may have already been
8792 // implicitly instantiated; that's fine.
8793 return false;
8794
8795 case TSK_ExplicitSpecialization:
8796 // C++ DR 259, C++0x [temp.explicit]p4:
8797 // For a given set of template parameters, if an explicit
8798 // instantiation of a template appears after a declaration of
8799 // an explicit specialization for that template, the explicit
8800 // instantiation has no effect.
8801 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8802 << PrevDecl;
8803 Diag(PrevDecl->getLocation(),
8804 diag::note_previous_template_specialization);
8805 HasNoEffect = true;
8806 return false;
8807
8808 case TSK_ExplicitInstantiationDeclaration:
8809 // We're explicitly instantiating a definition for something for which we
8810 // were previously asked to suppress instantiations. That's fine.
8811
8812 // C++0x [temp.explicit]p4:
8813 // For a given set of template parameters, if an explicit instantiation
8814 // of a template appears after a declaration of an explicit
8815 // specialization for that template, the explicit instantiation has no
8816 // effect.
8817 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8818 // Is there any previous explicit specialization declaration?
8819 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8820 HasNoEffect = true;
8821 break;
8822 }
8823 }
8824
8825 return false;
8826
8827 case TSK_ExplicitInstantiationDefinition:
8828 // C++0x [temp.spec]p5:
8829 // For a given template and a given set of template-arguments,
8830 // - an explicit instantiation definition shall appear at most once
8831 // in a program,
8832
8833 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8834 Diag(NewLoc, (getLangOpts().MSVCCompat)
8835 ? diag::ext_explicit_instantiation_duplicate
8836 : diag::err_explicit_instantiation_duplicate)
8837 << PrevDecl;
8838 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8839 diag::note_previous_explicit_instantiation);
8840 HasNoEffect = true;
8841 return false;
8842 }
8843 }
8844
8845 llvm_unreachable("Missing specialization/instantiation case?");
8846}
8847
8848/// Perform semantic analysis for the given dependent function
8849/// template specialization.
8850///
8851/// The only possible way to get a dependent function template specialization
8852/// is with a friend declaration, like so:
8853///
8854/// \code
8855/// template \<class T> void foo(T);
8856/// template \<class T> class A {
8857/// friend void foo<>(T);
8858/// };
8859/// \endcode
8860///
8861/// There really isn't any useful analysis we can do here, so we
8862/// just store the information.
8863bool
8864Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8865 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8866 LookupResult &Previous) {
8867 // Remove anything from Previous that isn't a function template in
8868 // the correct context.
8869 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8870 LookupResult::Filter F = Previous.makeFilter();
8871 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8872 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8873 while (F.hasNext()) {
8874 NamedDecl *D = F.next()->getUnderlyingDecl();
8875 if (!isa<FunctionTemplateDecl>(D)) {
8876 F.erase();
8877 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8878 continue;
8879 }
8880
8881 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8882 D->getDeclContext()->getRedeclContext())) {
8883 F.erase();
8884 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8885 continue;
8886 }
8887 }
8888 F.done();
8889
8890 if (Previous.empty()) {
8891 Diag(FD->getLocation(),
8892 diag::err_dependent_function_template_spec_no_match);
8893 for (auto &P : DiscardedCandidates)
8894 Diag(P.second->getLocation(),
8895 diag::note_dependent_function_template_spec_discard_reason)
8896 << P.first;
8897 return true;
8898 }
8899
8900 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8901 ExplicitTemplateArgs);
8902 return false;
8903}
8904
8905/// Perform semantic analysis for the given function template
8906/// specialization.
8907///
8908/// This routine performs all of the semantic analysis required for an
8909/// explicit function template specialization. On successful completion,
8910/// the function declaration \p FD will become a function template
8911/// specialization.
8912///
8913/// \param FD the function declaration, which will be updated to become a
8914/// function template specialization.
8915///
8916/// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8917/// if any. Note that this may be valid info even when 0 arguments are
8918/// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8919/// as it anyway contains info on the angle brackets locations.
8920///
8921/// \param Previous the set of declarations that may be specialized by
8922/// this function specialization.
8923///
8924/// \param QualifiedFriend whether this is a lookup for a qualified friend
8925/// declaration with no explicit template argument list that might be
8926/// befriending a function template specialization.
8927bool Sema::CheckFunctionTemplateSpecialization(
8928 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8929 LookupResult &Previous, bool QualifiedFriend) {
8930 // The set of function template specializations that could match this
8931 // explicit function template specialization.
8932 UnresolvedSet<8> Candidates;
8933 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8934 /*ForTakingAddress=*/false);
8935
8936 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8937 ConvertedTemplateArgs;
8938
8939 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8940 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8941 I != E; ++I) {
8942 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8943 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8944 // Only consider templates found within the same semantic lookup scope as
8945 // FD.
8946 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8947 Ovl->getDeclContext()->getRedeclContext()))
8948 continue;
8949
8950 // When matching a constexpr member function template specialization
8951 // against the primary template, we don't yet know whether the
8952 // specialization has an implicit 'const' (because we don't know whether
8953 // it will be a static member function until we know which template it
8954 // specializes), so adjust it now assuming it specializes this template.
8955 QualType FT = FD->getType();
8956 if (FD->isConstexpr()) {
8957 CXXMethodDecl *OldMD =
8958 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8959 if (OldMD && OldMD->isConst()) {
8960 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8961 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8962 EPI.TypeQuals.addConst();
8963 FT = Context.getFunctionType(FPT->getReturnType(),
8964 FPT->getParamTypes(), EPI);
8965 }
8966 }
8967
8968 TemplateArgumentListInfo Args;
8969 if (ExplicitTemplateArgs)
8970 Args = *ExplicitTemplateArgs;
8971
8972 // C++ [temp.expl.spec]p11:
8973 // A trailing template-argument can be left unspecified in the
8974 // template-id naming an explicit function template specialization
8975 // provided it can be deduced from the function argument type.
8976 // Perform template argument deduction to determine whether we may be
8977 // specializing this template.
8978 // FIXME: It is somewhat wasteful to build
8979 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8980 FunctionDecl *Specialization = nullptr;
8981 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8982 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8983 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8984 Info)) {
8985 // Template argument deduction failed; record why it failed, so
8986 // that we can provide nifty diagnostics.
8987 FailedCandidates.addCandidate().set(
8988 I.getPair(), FunTmpl->getTemplatedDecl(),
8989 MakeDeductionFailureInfo(Context, TDK, Info));
8990 (void)TDK;
8991 continue;
8992 }
8993
8994 // Target attributes are part of the cuda function signature, so
8995 // the deduced template's cuda target must match that of the
8996 // specialization. Given that C++ template deduction does not
8997 // take target attributes into account, we reject candidates
8998 // here that have a different target.
8999 if (LangOpts.CUDA &&
9000 IdentifyCUDATarget(Specialization,
9001 /* IgnoreImplicitHDAttr = */ true) !=
9002 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
9003 FailedCandidates.addCandidate().set(
9004 I.getPair(), FunTmpl->getTemplatedDecl(),
9005 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9006 continue;
9007 }
9008
9009 // Record this candidate.
9010 if (ExplicitTemplateArgs)
9011 ConvertedTemplateArgs[Specialization] = std::move(Args);
9012 Candidates.addDecl(Specialization, I.getAccess());
9013 }
9014 }
9015
9016 // For a qualified friend declaration (with no explicit marker to indicate
9017 // that a template specialization was intended), note all (template and
9018 // non-template) candidates.
9019 if (QualifiedFriend && Candidates.empty()) {
9020 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
9021 << FD->getDeclName() << FDLookupContext;
9022 // FIXME: We should form a single candidate list and diagnose all
9023 // candidates at once, to get proper sorting and limiting.
9024 for (auto *OldND : Previous) {
9025 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
9026 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
9027 }
9028 FailedCandidates.NoteCandidates(*this, FD->getLocation());
9029 return true;
9030 }
9031
9032 // Find the most specialized function template.
9033 UnresolvedSetIterator Result = getMostSpecialized(
9034 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
9035 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
9036 PDiag(diag::err_function_template_spec_ambiguous)
9037 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
9038 PDiag(diag::note_function_template_spec_matched));
9039
9040 if (Result == Candidates.end())
9041 return true;
9042
9043 // Ignore access information; it doesn't figure into redeclaration checking.
9044 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
9045
9046 FunctionTemplateSpecializationInfo *SpecInfo
9047 = Specialization->getTemplateSpecializationInfo();
9048 assert(SpecInfo && "Function template specialization info missing?");
9049
9050 // Note: do not overwrite location info if previous template
9051 // specialization kind was explicit.
9052 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
9053 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
9054 Specialization->setLocation(FD->getLocation());
9055 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
9056 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
9057 // function can differ from the template declaration with respect to
9058 // the constexpr specifier.
9059 // FIXME: We need an update record for this AST mutation.
9060 // FIXME: What if there are multiple such prior declarations (for instance,
9061 // from different modules)?
9062 Specialization->setConstexprKind(FD->getConstexprKind());
9063 }
9064
9065 // FIXME: Check if the prior specialization has a point of instantiation.
9066 // If so, we have run afoul of .
9067
9068 // If this is a friend declaration, then we're not really declaring
9069 // an explicit specialization.
9070 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
9071
9072 // Check the scope of this explicit specialization.
9073 if (!isFriend &&
9074 CheckTemplateSpecializationScope(*this,
9075 Specialization->getPrimaryTemplate(),
9076 Specialization, FD->getLocation(),
9077 false))
9078 return true;
9079
9080 // C++ [temp.expl.spec]p6:
9081 // If a template, a member template or the member of a class template is
9082 // explicitly specialized then that specialization shall be declared
9083 // before the first use of that specialization that would cause an implicit
9084 // instantiation to take place, in every translation unit in which such a
9085 // use occurs; no diagnostic is required.
9086 bool HasNoEffect = false;
9087 if (!isFriend &&
9088 CheckSpecializationInstantiationRedecl(FD->getLocation(),
9089 TSK_ExplicitSpecialization,
9090 Specialization,
9091 SpecInfo->getTemplateSpecializationKind(),
9092 SpecInfo->getPointOfInstantiation(),
9093 HasNoEffect))
9094 return true;
9095
9096 // Mark the prior declaration as an explicit specialization, so that later
9097 // clients know that this is an explicit specialization.
9098 if (!isFriend) {
9099 // Since explicit specializations do not inherit '=delete' from their
9100 // primary function template - check if the 'specialization' that was
9101 // implicitly generated (during template argument deduction for partial
9102 // ordering) from the most specialized of all the function templates that
9103 // 'FD' could have been specializing, has a 'deleted' definition. If so,
9104 // first check that it was implicitly generated during template argument
9105 // deduction by making sure it wasn't referenced, and then reset the deleted
9106 // flag to not-deleted, so that we can inherit that information from 'FD'.
9107 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
9108 !Specialization->getCanonicalDecl()->isReferenced()) {
9109 // FIXME: This assert will not hold in the presence of modules.
9110 assert(
9111 Specialization->getCanonicalDecl() == Specialization &&
9112 "This must be the only existing declaration of this specialization");
9113 // FIXME: We need an update record for this AST mutation.
9114 Specialization->setDeletedAsWritten(false);
9115 }
9116 // FIXME: We need an update record for this AST mutation.
9117 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9118 MarkUnusedFileScopedDecl(Specialization);
9119 }
9120
9121 // Turn the given function declaration into a function template
9122 // specialization, with the template arguments from the previous
9123 // specialization.
9124 // Take copies of (semantic and syntactic) template argument lists.
9125 const TemplateArgumentList* TemplArgs = new (Context)
9126 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
9127 FD->setFunctionTemplateSpecialization(
9128 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
9129 SpecInfo->getTemplateSpecializationKind(),
9130 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
9131
9132 // A function template specialization inherits the target attributes
9133 // of its template. (We require the attributes explicitly in the
9134 // code to match, but a template may have implicit attributes by
9135 // virtue e.g. of being constexpr, and it passes these implicit
9136 // attributes on to its specializations.)
9137 if (LangOpts.CUDA)
9138 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
9139
9140 // The "previous declaration" for this function template specialization is
9141 // the prior function template specialization.
9142 Previous.clear();
9143 Previous.addDecl(Specialization);
9144 return false;
9145}
9146
9147/// Perform semantic analysis for the given non-template member
9148/// specialization.
9149///
9150/// This routine performs all of the semantic analysis required for an
9151/// explicit member function specialization. On successful completion,
9152/// the function declaration \p FD will become a member function
9153/// specialization.
9154///
9155/// \param Member the member declaration, which will be updated to become a
9156/// specialization.
9157///
9158/// \param Previous the set of declarations, one of which may be specialized
9159/// by this function specialization; the set will be modified to contain the
9160/// redeclared member.
9161bool
9162Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
9163 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
9164
9165 // Try to find the member we are instantiating.
9166 NamedDecl *FoundInstantiation = nullptr;
9167 NamedDecl *Instantiation = nullptr;
9168 NamedDecl *InstantiatedFrom = nullptr;
9169 MemberSpecializationInfo *MSInfo = nullptr;
9170
9171 if (Previous.empty()) {
9172 // Nowhere to look anyway.
9173 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
9174 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
9175 I != E; ++I) {
9176 NamedDecl *D = (*I)->getUnderlyingDecl();
9177 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
9178 QualType Adjusted = Function->getType();
9179 if (!hasExplicitCallingConv(Adjusted))
9180 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
9181 // This doesn't handle deduced return types, but both function
9182 // declarations should be undeduced at this point.
9183 if (Context.hasSameType(Adjusted, Method->getType())) {
9184 FoundInstantiation = *I;
9185 Instantiation = Method;
9186 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
9187 MSInfo = Method->getMemberSpecializationInfo();
9188 break;
9189 }
9190 }
9191 }
9192 } else if (isa<VarDecl>(Member)) {
9193 VarDecl *PrevVar;
9194 if (Previous.isSingleResult() &&
9195 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
9196 if (PrevVar->isStaticDataMember()) {
9197 FoundInstantiation = Previous.getRepresentativeDecl();
9198 Instantiation = PrevVar;
9199 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
9200 MSInfo = PrevVar->getMemberSpecializationInfo();
9201 }
9202 } else if (isa<RecordDecl>(Member)) {
9203 CXXRecordDecl *PrevRecord;
9204 if (Previous.isSingleResult() &&
9205 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
9206 FoundInstantiation = Previous.getRepresentativeDecl();
9207 Instantiation = PrevRecord;
9208 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
9209 MSInfo = PrevRecord->getMemberSpecializationInfo();
9210 }
9211 } else if (isa<EnumDecl>(Member)) {
9212 EnumDecl *PrevEnum;
9213 if (Previous.isSingleResult() &&
9214 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
9215 FoundInstantiation = Previous.getRepresentativeDecl();
9216 Instantiation = PrevEnum;
9217 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
9218 MSInfo = PrevEnum->getMemberSpecializationInfo();
9219 }
9220 }
9221
9222 if (!Instantiation) {
9223 // There is no previous declaration that matches. Since member
9224 // specializations are always out-of-line, the caller will complain about
9225 // this mismatch later.
9226 return false;
9227 }
9228
9229 // A member specialization in a friend declaration isn't really declaring
9230 // an explicit specialization, just identifying a specific (possibly implicit)
9231 // specialization. Don't change the template specialization kind.
9232 //
9233 // FIXME: Is this really valid? Other compilers reject.
9234 if (Member->getFriendObjectKind() != Decl::FOK_None) {
9235 // Preserve instantiation information.
9236 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
9237 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
9238 cast<CXXMethodDecl>(InstantiatedFrom),
9239 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
9240 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
9241 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
9242 cast<CXXRecordDecl>(InstantiatedFrom),
9243 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
9244 }
9245
9246 Previous.clear();
9247 Previous.addDecl(FoundInstantiation);
9248 return false;
9249 }
9250
9251 // Make sure that this is a specialization of a member.
9252 if (!InstantiatedFrom) {
9253 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
9254 << Member;
9255 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
9256 return true;
9257 }
9258
9259 // C++ [temp.expl.spec]p6:
9260 // If a template, a member template or the member of a class template is
9261 // explicitly specialized then that specialization shall be declared
9262 // before the first use of that specialization that would cause an implicit
9263 // instantiation to take place, in every translation unit in which such a
9264 // use occurs; no diagnostic is required.
9265 assert(MSInfo && "Member specialization info missing?");
9266
9267 bool HasNoEffect = false;
9268 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
9269 TSK_ExplicitSpecialization,
9270 Instantiation,
9271 MSInfo->getTemplateSpecializationKind(),
9272 MSInfo->getPointOfInstantiation(),
9273 HasNoEffect))
9274 return true;
9275
9276 // Check the scope of this explicit specialization.
9277 if (CheckTemplateSpecializationScope(*this,
9278 InstantiatedFrom,
9279 Instantiation, Member->getLocation(),
9280 false))
9281 return true;
9282
9283 // Note that this member specialization is an "instantiation of" the
9284 // corresponding member of the original template.
9285 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
9286 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
9287 if (InstantiationFunction->getTemplateSpecializationKind() ==
9288 TSK_ImplicitInstantiation) {
9289 // Explicit specializations of member functions of class templates do not
9290 // inherit '=delete' from the member function they are specializing.
9291 if (InstantiationFunction->isDeleted()) {
9292 // FIXME: This assert will not hold in the presence of modules.
9293 assert(InstantiationFunction->getCanonicalDecl() ==
9294 InstantiationFunction);
9295 // FIXME: We need an update record for this AST mutation.
9296 InstantiationFunction->setDeletedAsWritten(false);
9297 }
9298 }
9299
9300 MemberFunction->setInstantiationOfMemberFunction(
9301 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9302 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
9303 MemberVar->setInstantiationOfStaticDataMember(
9304 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9305 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
9306 MemberClass->setInstantiationOfMemberClass(
9307 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9308 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
9309 MemberEnum->setInstantiationOfMemberEnum(
9310 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
9311 } else {
9312 llvm_unreachable("unknown member specialization kind");
9313 }
9314
9315 // Save the caller the trouble of having to figure out which declaration
9316 // this specialization matches.
9317 Previous.clear();
9318 Previous.addDecl(FoundInstantiation);
9319 return false;
9320}
9321
9322/// Complete the explicit specialization of a member of a class template by
9323/// updating the instantiated member to be marked as an explicit specialization.
9324///
9325/// \param OrigD The member declaration instantiated from the template.
9326/// \param Loc The location of the explicit specialization of the member.
9327template<typename DeclT>
9328static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
9329 SourceLocation Loc) {
9330 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
9331 return;
9332
9333 // FIXME: Inform AST mutation listeners of this AST mutation.
9334 // FIXME: If there are multiple in-class declarations of the member (from
9335 // multiple modules, or a declaration and later definition of a member type),
9336 // should we update all of them?
9337 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
9338 OrigD->setLocation(Loc);
9339}
9340
9341void Sema::CompleteMemberSpecialization(NamedDecl *Member,
9342 LookupResult &Previous) {
9343 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
9344 if (Instantiation == Member)
9345 return;
9346
9347 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
9348 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
9349 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
9350 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
9351 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
9352 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
9353 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
9354 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
9355 else
9356 llvm_unreachable("unknown member specialization kind");
9357}
9358
9359/// Check the scope of an explicit instantiation.
9360///
9361/// \returns true if a serious error occurs, false otherwise.
9362static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
9363 SourceLocation InstLoc,
9364 bool WasQualifiedName) {
9365 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
9366 DeclContext *CurContext = S.CurContext->getRedeclContext();
9367
9368 if (CurContext->isRecord()) {
9369 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
9370 << D;
9371 return true;
9372 }
9373
9374 // C++11 [temp.explicit]p3:
9375 // An explicit instantiation shall appear in an enclosing namespace of its
9376 // template. If the name declared in the explicit instantiation is an
9377 // unqualified name, the explicit instantiation shall appear in the
9378 // namespace where its template is declared or, if that namespace is inline
9379 // (7.3.1), any namespace from its enclosing namespace set.
9380 //
9381 // This is DR275, which we do not retroactively apply to C++98/03.
9382 if (WasQualifiedName) {
9383 if (CurContext->Encloses(OrigContext))
9384 return false;
9385 } else {
9386 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
9387 return false;
9388 }
9389
9390 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
9391 if (WasQualifiedName)
9392 S.Diag(InstLoc,
9393 S.getLangOpts().CPlusPlus11?
9394 diag::err_explicit_instantiation_out_of_scope :
9395 diag::warn_explicit_instantiation_out_of_scope_0x)
9396 << D << NS;
9397 else
9398 S.Diag(InstLoc,
9399 S.getLangOpts().CPlusPlus11?
9400 diag::err_explicit_instantiation_unqualified_wrong_namespace :
9401 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
9402 << D << NS;
9403 } else
9404 S.Diag(InstLoc,
9405 S.getLangOpts().CPlusPlus11?
9406 diag::err_explicit_instantiation_must_be_global :
9407 diag::warn_explicit_instantiation_must_be_global_0x)
9408 << D;
9409 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
9410 return false;
9411}
9412
9413/// Common checks for whether an explicit instantiation of \p D is valid.
9414static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
9415 SourceLocation InstLoc,
9416 bool WasQualifiedName,
9417 TemplateSpecializationKind TSK) {
9418 // C++ [temp.explicit]p13:
9419 // An explicit instantiation declaration shall not name a specialization of
9420 // a template with internal linkage.
9421 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9422 D->getFormalLinkage() == InternalLinkage) {
9423 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
9424 return true;
9425 }
9426
9427 // C++11 [temp.explicit]p3: [DR 275]
9428 // An explicit instantiation shall appear in an enclosing namespace of its
9429 // template.
9430 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
9431 return true;
9432
9433 return false;
9434}
9435
9436/// Determine whether the given scope specifier has a template-id in it.
9437static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
9438 if (!SS.isSet())
9439 return false;
9440
9441 // C++11 [temp.explicit]p3:
9442 // If the explicit instantiation is for a member function, a member class
9443 // or a static data member of a class template specialization, the name of
9444 // the class template specialization in the qualified-id for the member
9445 // name shall be a simple-template-id.
9446 //
9447 // C++98 has the same restriction, just worded differently.
9448 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
9449 NNS = NNS->getPrefix())
9450 if (const Type *T = NNS->getAsType())
9451 if (isa<TemplateSpecializationType>(T))
9452 return true;
9453
9454 return false;
9455}
9456
9457/// Make a dllexport or dllimport attr on a class template specialization take
9458/// effect.
9459static void dllExportImportClassTemplateSpecialization(
9460 Sema &S, ClassTemplateSpecializationDecl *Def) {
9461 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
9462 assert(A && "dllExportImportClassTemplateSpecialization called "
9463 "on Def without dllexport or dllimport");
9464
9465 // We reject explicit instantiations in class scope, so there should
9466 // never be any delayed exported classes to worry about.
9467 assert(S.DelayedDllExportClasses.empty() &&
9468 "delayed exports present at explicit instantiation");
9469 S.checkClassLevelDLLAttribute(Def);
9470
9471 // Propagate attribute to base class templates.
9472 for (auto &B : Def->bases()) {
9473 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
9474 B.getType()->getAsCXXRecordDecl()))
9475 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
9476 }
9477
9478 S.referenceDLLExportedClassMethods();
9479}
9480
9481// Explicit instantiation of a class template specialization
9482DeclResult Sema::ActOnExplicitInstantiation(
9483 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
9484 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
9485 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
9486 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
9487 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
9488 // Find the class template we're specializing
9489 TemplateName Name = TemplateD.get();
9490 TemplateDecl *TD = Name.getAsTemplateDecl();
9491 // Check that the specialization uses the same tag kind as the
9492 // original template.
9493 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9494 assert(Kind != TTK_Enum &&
9495 "Invalid enum tag in class template explicit instantiation!");
9496
9497 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
9498
9499 if (!ClassTemplate) {
9500 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
9501 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
9502 Diag(TD->getLocation(), diag::note_previous_use);
9503 return true;
9504 }
9505
9506 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
9507 Kind, /*isDefinition*/false, KWLoc,
9508 ClassTemplate->getIdentifier())) {
9509 Diag(KWLoc, diag::err_use_with_wrong_tag)
9510 << ClassTemplate
9511 << FixItHint::CreateReplacement(KWLoc,
9512 ClassTemplate->getTemplatedDecl()->getKindName());
9513 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
9514 diag::note_previous_use);
9515 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
9516 }
9517
9518 // C++0x [temp.explicit]p2:
9519 // There are two forms of explicit instantiation: an explicit instantiation
9520 // definition and an explicit instantiation declaration. An explicit
9521 // instantiation declaration begins with the extern keyword. [...]
9522 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
9523 ? TSK_ExplicitInstantiationDefinition
9524 : TSK_ExplicitInstantiationDeclaration;
9525
9526 if (TSK == TSK_ExplicitInstantiationDeclaration &&
9527 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9528 // Check for dllexport class template instantiation declarations,
9529 // except for MinGW mode.
9530 for (const ParsedAttr &AL : Attr) {
9531 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9532 Diag(ExternLoc,
9533 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9534 Diag(AL.getLoc(), diag::note_attribute);
9535 break;
9536 }
9537 }
9538
9539 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
9540 Diag(ExternLoc,
9541 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9542 Diag(A->getLocation(), diag::note_attribute);
9543 }
9544 }
9545
9546 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9547 // instantiation declarations for most purposes.
9548 bool DLLImportExplicitInstantiationDef = false;
9549 if (TSK == TSK_ExplicitInstantiationDefinition &&
9550 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
9551 // Check for dllimport class template instantiation definitions.
9552 bool DLLImport =
9553 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
9554 for (const ParsedAttr &AL : Attr) {
9555 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9556 DLLImport = true;
9557 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9558 // dllexport trumps dllimport here.
9559 DLLImport = false;
9560 break;
9561 }
9562 }
9563 if (DLLImport) {
9564 TSK = TSK_ExplicitInstantiationDeclaration;
9565 DLLImportExplicitInstantiationDef = true;
9566 }
9567 }
9568
9569 // Translate the parser's template argument list in our AST format.
9570 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9571 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9572
9573 // Check that the template argument list is well-formed for this
9574 // template.
9575 SmallVector<TemplateArgument, 4> Converted;
9576 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9577 TemplateArgs, false, Converted,
9578 /*UpdateArgsWithConversion=*/true))
9579 return true;
9580
9581 // Find the class template specialization declaration that
9582 // corresponds to these arguments.
9583 void *InsertPos = nullptr;
9584 ClassTemplateSpecializationDecl *PrevDecl
9585 = ClassTemplate->findSpecialization(Converted, InsertPos);
9586
9587 TemplateSpecializationKind PrevDecl_TSK
9588 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9589
9590 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9591 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9592 // Check for dllexport class template instantiation definitions in MinGW
9593 // mode, if a previous declaration of the instantiation was seen.
9594 for (const ParsedAttr &AL : Attr) {
9595 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9596 Diag(AL.getLoc(),
9597 diag::warn_attribute_dllexport_explicit_instantiation_def);
9598 break;
9599 }
9600 }
9601 }
9602
9603 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9604 SS.isSet(), TSK))
9605 return true;
9606
9607 ClassTemplateSpecializationDecl *Specialization = nullptr;
9608
9609 bool HasNoEffect = false;
9610 if (PrevDecl) {
9611 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9612 PrevDecl, PrevDecl_TSK,
9613 PrevDecl->getPointOfInstantiation(),
9614 HasNoEffect))
9615 return PrevDecl;
9616
9617 // Even though HasNoEffect == true means that this explicit instantiation
9618 // has no effect on semantics, we go on to put its syntax in the AST.
9619
9620 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9621 PrevDecl_TSK == TSK_Undeclared) {
9622 // Since the only prior class template specialization with these
9623 // arguments was referenced but not declared, reuse that
9624 // declaration node as our own, updating the source location
9625 // for the template name to reflect our new declaration.
9626 // (Other source locations will be updated later.)
9627 Specialization = PrevDecl;
9628 Specialization->setLocation(TemplateNameLoc);
9629 PrevDecl = nullptr;
9630 }
9631
9632 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9633 DLLImportExplicitInstantiationDef) {
9634 // The new specialization might add a dllimport attribute.
9635 HasNoEffect = false;
9636 }
9637 }
9638
9639 if (!Specialization) {
9640 // Create a new class template specialization declaration node for
9641 // this explicit specialization.
9642 Specialization
9643 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9644 ClassTemplate->getDeclContext(),
9645 KWLoc, TemplateNameLoc,
9646 ClassTemplate,
9647 Converted,
9648 PrevDecl);
9649 SetNestedNameSpecifier(*this, Specialization, SS);
9650
9651 if (!HasNoEffect && !PrevDecl) {
9652 // Insert the new specialization.
9653 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9654 }
9655 }
9656
9657 // Build the fully-sugared type for this explicit instantiation as
9658 // the user wrote in the explicit instantiation itself. This means
9659 // that we'll pretty-print the type retrieved from the
9660 // specialization's declaration the way that the user actually wrote
9661 // the explicit instantiation, rather than formatting the name based
9662 // on the "canonical" representation used to store the template
9663 // arguments in the specialization.
9664 TypeSourceInfo *WrittenTy
9665 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9666 TemplateArgs,
9667 Context.getTypeDeclType(Specialization));
9668 Specialization->setTypeAsWritten(WrittenTy);
9669
9670 // Set source locations for keywords.
9671 Specialization->setExternLoc(ExternLoc);
9672 Specialization->setTemplateKeywordLoc(TemplateLoc);
9673 Specialization->setBraceRange(SourceRange());
9674
9675 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9676 ProcessDeclAttributeList(S, Specialization, Attr);
9677
9678 // Add the explicit instantiation into its lexical context. However,
9679 // since explicit instantiations are never found by name lookup, we
9680 // just put it into the declaration context directly.
9681 Specialization->setLexicalDeclContext(CurContext);
9682 CurContext->addDecl(Specialization);
9683
9684 // Syntax is now OK, so return if it has no other effect on semantics.
9685 if (HasNoEffect) {
9686 // Set the template specialization kind.
9687 Specialization->setTemplateSpecializationKind(TSK);
9688 return Specialization;
9689 }
9690
9691 // C++ [temp.explicit]p3:
9692 // A definition of a class template or class member template
9693 // shall be in scope at the point of the explicit instantiation of
9694 // the class template or class member template.
9695 //
9696 // This check comes when we actually try to perform the
9697 // instantiation.
9698 ClassTemplateSpecializationDecl *Def
9699 = cast_or_null<ClassTemplateSpecializationDecl>(
9700 Specialization->getDefinition());
9701 if (!Def)
9702 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9703 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9704 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9705 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9706 }
9707
9708 // Instantiate the members of this class template specialization.
9709 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9710 Specialization->getDefinition());
9711 if (Def) {
9712 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9713 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9714 // TSK_ExplicitInstantiationDefinition
9715 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9716 (TSK == TSK_ExplicitInstantiationDefinition ||
9717 DLLImportExplicitInstantiationDef)) {
9718 // FIXME: Need to notify the ASTMutationListener that we did this.
9719 Def->setTemplateSpecializationKind(TSK);
9720
9721 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9722 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
9723 !Context.getTargetInfo().getTriple().isPS4CPU())) {
9724 // An explicit instantiation definition can add a dll attribute to a
9725 // template with a previous instantiation declaration. MinGW doesn't
9726 // allow this.
9727 auto *A = cast<InheritableAttr>(
9728 getDLLAttr(Specialization)->clone(getASTContext()));
9729 A->setInherited(true);
9730 Def->addAttr(A);
9731 dllExportImportClassTemplateSpecialization(*this, Def);
9732 }
9733 }
9734
9735 // Fix a TSK_ImplicitInstantiation followed by a
9736 // TSK_ExplicitInstantiationDefinition
9737 bool NewlyDLLExported =
9738 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9739 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9740 (Context.getTargetInfo().shouldDLLImportComdatSymbols() &&
9741 !Context.getTargetInfo().getTriple().isPS4CPU())) {
9742 // An explicit instantiation definition can add a dll attribute to a
9743 // template with a previous implicit instantiation. MinGW doesn't allow
9744 // this. We limit clang to only adding dllexport, to avoid potentially
9745 // strange codegen behavior. For example, if we extend this conditional
9746 // to dllimport, and we have a source file calling a method on an
9747 // implicitly instantiated template class instance and then declaring a
9748 // dllimport explicit instantiation definition for the same template
9749 // class, the codegen for the method call will not respect the dllimport,
9750 // while it will with cl. The Def will already have the DLL attribute,
9751 // since the Def and Specialization will be the same in the case of
9752 // Old_TSK == TSK_ImplicitInstantiation, and we already added the
9753 // attribute to the Specialization; we just need to make it take effect.
9754 assert(Def == Specialization &&
9755 "Def and Specialization should match for implicit instantiation");
9756 dllExportImportClassTemplateSpecialization(*this, Def);
9757 }
9758
9759 // In MinGW mode, export the template instantiation if the declaration
9760 // was marked dllexport.
9761 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9762 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9763 PrevDecl->hasAttr<DLLExportAttr>()) {
9764 dllExportImportClassTemplateSpecialization(*this, Def);
9765 }
9766
9767 if (Def->hasAttr<MSInheritanceAttr>()) {
9768 Specialization->addAttr(Def->getAttr<MSInheritanceAttr>());
9769 Consumer.AssignInheritanceModel(Specialization);
9770 }
9771
9772 // Set the template specialization kind. Make sure it is set before
9773 // instantiating the members which will trigger ASTConsumer callbacks.
9774 Specialization->setTemplateSpecializationKind(TSK);
9775 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9776 } else {
9777
9778 // Set the template specialization kind.
9779 Specialization->setTemplateSpecializationKind(TSK);
9780 }
9781
9782 return Specialization;
9783}
9784
9785// Explicit instantiation of a member class of a class template.
9786DeclResult
9787Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9788 SourceLocation TemplateLoc, unsigned TagSpec,
9789 SourceLocation KWLoc, CXXScopeSpec &SS,
9790 IdentifierInfo *Name, SourceLocation NameLoc,
9791 const ParsedAttributesView &Attr) {
9792
9793 bool Owned = false;
9794 bool IsDependent = false;
9795 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9796 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9797 /*ModulePrivateLoc=*/SourceLocation(),
9798 MultiTemplateParamsArg(), Owned, IsDependent,
9799 SourceLocation(), false, TypeResult(),
9800 /*IsTypeSpecifier*/false,
9801 /*IsTemplateParamOrArg*/false);
9802 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9803
9804 if (!TagD)
9805 return true;
9806
9807 TagDecl *Tag = cast<TagDecl>(TagD);
9808 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9809
9810 if (Tag->isInvalidDecl())
9811 return true;
9812
9813 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9814 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9815 if (!Pattern) {
9816 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9817 << Context.getTypeDeclType(Record);
9818 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9819 return true;
9820 }
9821
9822 // C++0x [temp.explicit]p2:
9823 // If the explicit instantiation is for a class or member class, the
9824 // elaborated-type-specifier in the declaration shall include a
9825 // simple-template-id.
9826 //
9827 // C++98 has the same restriction, just worded differently.
9828 if (!ScopeSpecifierHasTemplateId(SS))
9829 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9830 << Record << SS.getRange();
9831
9832 // C++0x [temp.explicit]p2:
9833 // There are two forms of explicit instantiation: an explicit instantiation
9834 // definition and an explicit instantiation declaration. An explicit
9835 // instantiation declaration begins with the extern keyword. [...]
9836 TemplateSpecializationKind TSK
9837 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9838 : TSK_ExplicitInstantiationDeclaration;
9839
9840 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9841
9842 // Verify that it is okay to explicitly instantiate here.
9843 CXXRecordDecl *PrevDecl
9844 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9845 if (!PrevDecl && Record->getDefinition())
9846 PrevDecl = Record;
9847 if (PrevDecl) {
9848 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9849 bool HasNoEffect = false;
9850 assert(MSInfo && "No member specialization information?");
9851 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9852 PrevDecl,
9853 MSInfo->getTemplateSpecializationKind(),
9854 MSInfo->getPointOfInstantiation(),
9855 HasNoEffect))
9856 return true;
9857 if (HasNoEffect)
9858 return TagD;
9859 }
9860
9861 CXXRecordDecl *RecordDef
9862 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9863 if (!RecordDef) {
9864 // C++ [temp.explicit]p3:
9865 // A definition of a member class of a class template shall be in scope
9866 // at the point of an explicit instantiation of the member class.
9867 CXXRecordDecl *Def
9868 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9869 if (!Def) {
9870 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9871 << 0 << Record->getDeclName() << Record->getDeclContext();
9872 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9873 << Pattern;
9874 return true;
9875 } else {
9876 if (InstantiateClass(NameLoc, Record, Def,
9877 getTemplateInstantiationArgs(Record),
9878 TSK))
9879 return true;
9880
9881 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9882 if (!RecordDef)
9883 return true;
9884 }
9885 }
9886
9887 // Instantiate all of the members of the class.
9888 InstantiateClassMembers(NameLoc, RecordDef,
9889 getTemplateInstantiationArgs(Record), TSK);
9890
9891 if (TSK == TSK_ExplicitInstantiationDefinition)
9892 MarkVTableUsed(NameLoc, RecordDef, true);
9893
9894 // FIXME: We don't have any representation for explicit instantiations of
9895 // member classes. Such a representation is not needed for compilation, but it
9896 // should be available for clients that want to see all of the declarations in
9897 // the source code.
9898 return TagD;
9899}
9900
9901DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9902 SourceLocation ExternLoc,
9903 SourceLocation TemplateLoc,
9904 Declarator &D) {
9905 // Explicit instantiations always require a name.
9906 // TODO: check if/when DNInfo should replace Name.
9907 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9908 DeclarationName Name = NameInfo.getName();
9909 if (!Name) {
9910 if (!D.isInvalidType())
9911 Diag(D.getDeclSpec().getBeginLoc(),
9912 diag::err_explicit_instantiation_requires_name)
9913 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9914
9915 return true;
9916 }
9917
9918 // The scope passed in may not be a decl scope. Zip up the scope tree until
9919 // we find one that is.
9920 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9921 (S->getFlags() & Scope::TemplateParamScope) != 0)
9922 S = S->getParent();
9923
9924 // Determine the type of the declaration.
9925 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9926 QualType R = T->getType();
9927 if (R.isNull())
9928 return true;
9929
9930 // C++ [dcl.stc]p1:
9931 // A storage-class-specifier shall not be specified in [...] an explicit
9932 // instantiation (14.7.2) directive.
9933 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9934 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9935 << Name;
9936 return true;
9937 } else if (D.getDeclSpec().getStorageClassSpec()
9938 != DeclSpec::SCS_unspecified) {
9939 // Complain about then remove the storage class specifier.
9940 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9941 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9942
9943 D.getMutableDeclSpec().ClearStorageClassSpecs();
9944 }
9945
9946 // C++0x [temp.explicit]p1:
9947 // [...] An explicit instantiation of a function template shall not use the
9948 // inline or constexpr specifiers.
9949 // Presumably, this also applies to member functions of class templates as
9950 // well.
9951 if (D.getDeclSpec().isInlineSpecified())
9952 Diag(D.getDeclSpec().getInlineSpecLoc(),
9953 getLangOpts().CPlusPlus11 ?
9954 diag::err_explicit_instantiation_inline :
9955 diag::warn_explicit_instantiation_inline_0x)
9956 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9957 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9958 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9959 // not already specified.
9960 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9961 diag::err_explicit_instantiation_constexpr);
9962
9963 // A deduction guide is not on the list of entities that can be explicitly
9964 // instantiated.
9965 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9966 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9967 << /*explicit instantiation*/ 0;
9968 return true;
9969 }
9970
9971 // C++0x [temp.explicit]p2:
9972 // There are two forms of explicit instantiation: an explicit instantiation
9973 // definition and an explicit instantiation declaration. An explicit
9974 // instantiation declaration begins with the extern keyword. [...]
9975 TemplateSpecializationKind TSK
9976 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9977 : TSK_ExplicitInstantiationDeclaration;
9978
9979 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9980 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9981
9982 if (!R->isFunctionType()) {
9983 // C++ [temp.explicit]p1:
9984 // A [...] static data member of a class template can be explicitly
9985 // instantiated from the member definition associated with its class
9986 // template.
9987 // C++1y [temp.explicit]p1:
9988 // A [...] variable [...] template specialization can be explicitly
9989 // instantiated from its template.
9990 if (Previous.isAmbiguous())
9991 return true;
9992
9993 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9994 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9995
9996 if (!PrevTemplate) {
9997 if (!Prev || !Prev->isStaticDataMember()) {
9998 // We expect to see a static data member here.
9999 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
10000 << Name;
10001 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10002 P != PEnd; ++P)
10003 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
10004 return true;
10005 }
10006
10007 if (!Prev->getInstantiatedFromStaticDataMember()) {
10008 // FIXME: Check for explicit specialization?
10009 Diag(D.getIdentifierLoc(),
10010 diag::err_explicit_instantiation_data_member_not_instantiated)
10011 << Prev;
10012 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
10013 // FIXME: Can we provide a note showing where this was declared?
10014 return true;
10015 }
10016 } else {
10017 // Explicitly instantiate a variable template.
10018
10019 // C++1y [dcl.spec.auto]p6:
10020 // ... A program that uses auto or decltype(auto) in a context not
10021 // explicitly allowed in this section is ill-formed.
10022 //
10023 // This includes auto-typed variable template instantiations.
10024 if (R->isUndeducedType()) {
10025 Diag(T->getTypeLoc().getBeginLoc(),
10026 diag::err_auto_not_allowed_var_inst);
10027 return true;
10028 }
10029
10030 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
10031 // C++1y [temp.explicit]p3:
10032 // If the explicit instantiation is for a variable, the unqualified-id
10033 // in the declaration shall be a template-id.
10034 Diag(D.getIdentifierLoc(),
10035 diag::err_explicit_instantiation_without_template_id)
10036 << PrevTemplate;
10037 Diag(PrevTemplate->getLocation(),
10038 diag::note_explicit_instantiation_here);
10039 return true;
10040 }
10041
10042 // Translate the parser's template argument list into our AST format.
10043 TemplateArgumentListInfo TemplateArgs =
10044 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10045
10046 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
10047 D.getIdentifierLoc(), TemplateArgs);
10048 if (Res.isInvalid())
10049 return true;
10050
10051 if (!Res.isUsable()) {
10052 // We somehow specified dependent template arguments in an explicit
10053 // instantiation. This should probably only happen during error
10054 // recovery.
10055 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_dependent);
10056 return true;
10057 }
10058
10059 // Ignore access control bits, we don't need them for redeclaration
10060 // checking.
10061 Prev = cast<VarDecl>(Res.get());
10062 }
10063
10064 // C++0x [temp.explicit]p2:
10065 // If the explicit instantiation is for a member function, a member class
10066 // or a static data member of a class template specialization, the name of
10067 // the class template specialization in the qualified-id for the member
10068 // name shall be a simple-template-id.
10069 //
10070 // C++98 has the same restriction, just worded differently.
10071 //
10072 // This does not apply to variable template specializations, where the
10073 // template-id is in the unqualified-id instead.
10074 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
10075 Diag(D.getIdentifierLoc(),
10076 diag::ext_explicit_instantiation_without_qualified_id)
10077 << Prev << D.getCXXScopeSpec().getRange();
10078
10079 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
10080
10081 // Verify that it is okay to explicitly instantiate here.
10082 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
10083 SourceLocation POI = Prev->getPointOfInstantiation();
10084 bool HasNoEffect = false;
10085 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
10086 PrevTSK, POI, HasNoEffect))
10087 return true;
10088
10089 if (!HasNoEffect) {
10090 // Instantiate static data member or variable template.
10091 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10092 // Merge attributes.
10093 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
10094 if (TSK == TSK_ExplicitInstantiationDefinition)
10095 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
10096 }
10097
10098 // Check the new variable specialization against the parsed input.
10099 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
10100 Diag(T->getTypeLoc().getBeginLoc(),
10101 diag::err_invalid_var_template_spec_type)
10102 << 0 << PrevTemplate << R << Prev->getType();
10103 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
10104 << 2 << PrevTemplate->getDeclName();
10105 return true;
10106 }
10107
10108 // FIXME: Create an ExplicitInstantiation node?
10109 return (Decl*) nullptr;
10110 }
10111
10112 // If the declarator is a template-id, translate the parser's template
10113 // argument list into our AST format.
10114 bool HasExplicitTemplateArgs = false;
10115 TemplateArgumentListInfo TemplateArgs;
10116 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
10117 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
10118 HasExplicitTemplateArgs = true;
10119 }
10120
10121 // C++ [temp.explicit]p1:
10122 // A [...] function [...] can be explicitly instantiated from its template.
10123 // A member function [...] of a class template can be explicitly
10124 // instantiated from the member definition associated with its class
10125 // template.
10126 UnresolvedSet<8> TemplateMatches;
10127 FunctionDecl *NonTemplateMatch = nullptr;
10128 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
10129 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
10130 P != PEnd; ++P) {
10131 NamedDecl *Prev = *P;
10132 if (!HasExplicitTemplateArgs) {
10133 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
10134 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
10135 /*AdjustExceptionSpec*/true);
10136 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
10137 if (Method->getPrimaryTemplate()) {
10138 TemplateMatches.addDecl(Method, P.getAccess());
10139 } else {
10140 // FIXME: Can this assert ever happen? Needs a test.
10141 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
10142 NonTemplateMatch = Method;
10143 }
10144 }
10145 }
10146 }
10147
10148 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
10149 if (!FunTmpl)
10150 continue;
10151
10152 TemplateDeductionInfo Info(FailedCandidates.getLocation());
10153 FunctionDecl *Specialization = nullptr;
10154 if (TemplateDeductionResult TDK
10155 = DeduceTemplateArguments(FunTmpl,
10156 (HasExplicitTemplateArgs ? &TemplateArgs
10157 : nullptr),
10158 R, Specialization, Info)) {
10159 // Keep track of almost-matches.
10160 FailedCandidates.addCandidate()
10161 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
10162 MakeDeductionFailureInfo(Context, TDK, Info));
10163 (void)TDK;
10164 continue;
10165 }
10166
10167 // Target attributes are part of the cuda function signature, so
10168 // the cuda target of the instantiated function must match that of its
10169 // template. Given that C++ template deduction does not take
10170 // target attributes into account, we reject candidates here that
10171 // have a different target.
10172 if (LangOpts.CUDA &&
10173 IdentifyCUDATarget(Specialization,
10174 /* IgnoreImplicitHDAttr = */ true) !=
10175 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
10176 FailedCandidates.addCandidate().set(
10177 P.getPair(), FunTmpl->getTemplatedDecl(),
10178 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
10179 continue;
10180 }
10181
10182 TemplateMatches.addDecl(Specialization, P.getAccess());
10183 }
10184
10185 FunctionDecl *Specialization = NonTemplateMatch;
10186 if (!Specialization) {
10187 // Find the most specialized function template specialization.
10188 UnresolvedSetIterator Result = getMostSpecialized(
10189 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
10190 D.getIdentifierLoc(),
10191 PDiag(diag::err_explicit_instantiation_not_known) << Name,
10192 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
10193 PDiag(diag::note_explicit_instantiation_candidate));
10194
10195 if (Result == TemplateMatches.end())
10196 return true;
10197
10198 // Ignore access control bits, we don't need them for redeclaration checking.
10199 Specialization = cast<FunctionDecl>(*Result);
10200 }
10201
10202 // C++11 [except.spec]p4
10203 // In an explicit instantiation an exception-specification may be specified,
10204 // but is not required.
10205 // If an exception-specification is specified in an explicit instantiation
10206 // directive, it shall be compatible with the exception-specifications of
10207 // other declarations of that function.
10208 if (auto *FPT = R->getAs<FunctionProtoType>())
10209 if (FPT->hasExceptionSpec()) {
10210 unsigned DiagID =
10211 diag::err_mismatched_exception_spec_explicit_instantiation;
10212 if (getLangOpts().MicrosoftExt)
10213 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
10214 bool Result = CheckEquivalentExceptionSpec(
10215 PDiag(DiagID) << Specialization->getType(),
10216 PDiag(diag::note_explicit_instantiation_here),
10217 Specialization->getType()->getAs<FunctionProtoType>(),
10218 Specialization->getLocation(), FPT, D.getBeginLoc());
10219 // In Microsoft mode, mismatching exception specifications just cause a
10220 // warning.
10221 if (!getLangOpts().MicrosoftExt && Result)
10222 return true;
10223 }
10224
10225 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
10226 Diag(D.getIdentifierLoc(),
10227 diag::err_explicit_instantiation_member_function_not_instantiated)
10228 << Specialization
10229 << (Specialization->getTemplateSpecializationKind() ==
10230 TSK_ExplicitSpecialization);
10231 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
10232 return true;
10233 }
10234
10235 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
10236 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
10237 PrevDecl = Specialization;
10238
10239 if (PrevDecl) {
10240 bool HasNoEffect = false;
10241 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
10242 PrevDecl,
10243 PrevDecl->getTemplateSpecializationKind(),
10244 PrevDecl->getPointOfInstantiation(),
10245 HasNoEffect))
10246 return true;
10247
10248 // FIXME: We may still want to build some representation of this
10249 // explicit specialization.
10250 if (HasNoEffect)
10251 return (Decl*) nullptr;
10252 }
10253
10254 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
10255 // functions
10256 // valarray<size_t>::valarray(size_t) and
10257 // valarray<size_t>::~valarray()
10258 // that it declared to have internal linkage with the internal_linkage
10259 // attribute. Ignore the explicit instantiation declaration in this case.
10260 if (Specialization->hasAttr<InternalLinkageAttr>() &&
10261 TSK == TSK_ExplicitInstantiationDeclaration) {
10262 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
10263 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
10264 RD->isInStdNamespace())
10265 return (Decl*) nullptr;
10266 }
10267
10268 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
10269
10270 // In MSVC mode, dllimported explicit instantiation definitions are treated as
10271 // instantiation declarations.
10272 if (TSK == TSK_ExplicitInstantiationDefinition &&
10273 Specialization->hasAttr<DLLImportAttr>() &&
10274 Context.getTargetInfo().getCXXABI().isMicrosoft())
10275 TSK = TSK_ExplicitInstantiationDeclaration;
10276
10277 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
10278
10279 if (Specialization->isDefined()) {
10280 // Let the ASTConsumer know that this function has been explicitly
10281 // instantiated now, and its linkage might have changed.
10282 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
10283 } else if (TSK == TSK_ExplicitInstantiationDefinition)
10284 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
10285
10286 // C++0x [temp.explicit]p2:
10287 // If the explicit instantiation is for a member function, a member class
10288 // or a static data member of a class template specialization, the name of
10289 // the class template specialization in the qualified-id for the member
10290 // name shall be a simple-template-id.
10291 //
10292 // C++98 has the same restriction, just worded differently.
10293 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
10294 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
10295 D.getCXXScopeSpec().isSet() &&
10296 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
10297 Diag(D.getIdentifierLoc(),
10298 diag::ext_explicit_instantiation_without_qualified_id)
10299 << Specialization << D.getCXXScopeSpec().getRange();
10300
10301 CheckExplicitInstantiation(
10302 *this,
10303 FunTmpl ? (NamedDecl *)FunTmpl
10304 : Specialization->getInstantiatedFromMemberFunction(),
10305 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
10306
10307 // FIXME: Create some kind of ExplicitInstantiationDecl here.
10308 return (Decl*) nullptr;
10309}
10310
10311TypeResult
10312Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
10313 const CXXScopeSpec &SS, IdentifierInfo *Name,
10314 SourceLocation TagLoc, SourceLocation NameLoc) {
10315 // This has to hold, because SS is expected to be defined.
10316 assert(Name && "Expected a name in a dependent tag");
10317
10318 NestedNameSpecifier *NNS = SS.getScopeRep();
10319 if (!NNS)
10320 return true;
10321
10322 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
10323
10324 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
10325 Diag(NameLoc, diag::err_dependent_tag_decl)
10326 << (TUK == TUK_Definition) << Kind << SS.getRange();
10327 return true;
10328 }
10329
10330 // Create the resulting type.
10331 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
10332 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
10333
10334 // Create type-source location information for this type.
10335 TypeLocBuilder TLB;
10336 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
10337 TL.setElaboratedKeywordLoc(TagLoc);
10338 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10339 TL.setNameLoc(NameLoc);
10340 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
10341}
10342
10343TypeResult
10344Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
10345 const CXXScopeSpec &SS, const IdentifierInfo &II,
10346 SourceLocation IdLoc) {
10347 if (SS.isInvalid())
10348 return true;
10349
10350 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10351 Diag(TypenameLoc,
10352 getLangOpts().CPlusPlus11 ?
10353 diag::warn_cxx98_compat_typename_outside_of_template :
10354 diag::ext_typename_outside_of_template)
10355 << FixItHint::CreateRemoval(TypenameLoc);
10356
10357 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10358 TypeSourceInfo *TSI = nullptr;
10359 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
10360 TypenameLoc, QualifierLoc, II, IdLoc, &TSI,
10361 /*DeducedTSTContext=*/true);
10362 if (T.isNull())
10363 return true;
10364 return CreateParsedType(T, TSI);
10365}
10366
10367TypeResult
10368Sema::ActOnTypenameType(Scope *S,
10369 SourceLocation TypenameLoc,
10370 const CXXScopeSpec &SS,
10371 SourceLocation TemplateKWLoc,
10372 TemplateTy TemplateIn,
10373 IdentifierInfo *TemplateII,
10374 SourceLocation TemplateIILoc,
10375 SourceLocation LAngleLoc,
10376 ASTTemplateArgsPtr TemplateArgsIn,
10377 SourceLocation RAngleLoc) {
10378 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
10379 Diag(TypenameLoc,
10380 getLangOpts().CPlusPlus11 ?
10381 diag::warn_cxx98_compat_typename_outside_of_template :
10382 diag::ext_typename_outside_of_template)
10383 << FixItHint::CreateRemoval(TypenameLoc);
10384
10385 // Strangely, non-type results are not ignored by this lookup, so the
10386 // program is ill-formed if it finds an injected-class-name.
10387 if (TypenameLoc.isValid()) {
10388 auto *LookupRD =
10389 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
10390 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
10391 Diag(TemplateIILoc,
10392 diag::ext_out_of_line_qualified_id_type_names_constructor)
10393 << TemplateII << 0 /*injected-class-name used as template name*/
10394 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
10395 }
10396 }
10397
10398 // Translate the parser's template argument list in our AST format.
10399 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
10400 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
10401
10402 TemplateName Template = TemplateIn.get();
10403 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
10404 // Construct a dependent template specialization type.
10405 assert(DTN && "dependent template has non-dependent name?");
10406 assert(DTN->getQualifier() == SS.getScopeRep());
10407 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
10408 DTN->getQualifier(),
10409 DTN->getIdentifier(),
10410 TemplateArgs);
10411
10412 // Create source-location information for this type.
10413 TypeLocBuilder Builder;
10414 DependentTemplateSpecializationTypeLoc SpecTL
10415 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
10416 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
10417 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
10418 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10419 SpecTL.setTemplateNameLoc(TemplateIILoc);
10420 SpecTL.setLAngleLoc(LAngleLoc);
10421 SpecTL.setRAngleLoc(RAngleLoc);
10422 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10423 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10424 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
10425 }
10426
10427 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
10428 if (T.isNull())
10429 return true;
10430
10431 // Provide source-location information for the template specialization type.
10432 TypeLocBuilder Builder;
10433 TemplateSpecializationTypeLoc SpecTL
10434 = Builder.push<TemplateSpecializationTypeLoc>(T);
10435 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
10436 SpecTL.setTemplateNameLoc(TemplateIILoc);
10437 SpecTL.setLAngleLoc(LAngleLoc);
10438 SpecTL.setRAngleLoc(RAngleLoc);
10439 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
10440 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
10441
10442 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
10443 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
10444 TL.setElaboratedKeywordLoc(TypenameLoc);
10445 TL.setQualifierLoc(SS.getWithLocInContext(Context));
10446
10447 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
10448 return CreateParsedType(T, TSI);
10449}
10450
10451
10452/// Determine whether this failed name lookup should be treated as being
10453/// disabled by a usage of std::enable_if.
10454static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
10455 SourceRange &CondRange, Expr *&Cond) {
10456 // We must be looking for a ::type...
10457 if (!II.isStr("type"))
10458 return false;
10459
10460 // ... within an explicitly-written template specialization...
10461 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
10462 return false;
10463 TypeLoc EnableIfTy = NNS.getTypeLoc();
10464 TemplateSpecializationTypeLoc EnableIfTSTLoc =
10465 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
10466 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
10467 return false;
10468 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
10469
10470 // ... which names a complete class template declaration...
10471 const TemplateDecl *EnableIfDecl =
10472 EnableIfTST->getTemplateName().getAsTemplateDecl();
10473 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
10474 return false;
10475
10476 // ... called "enable_if".
10477 const IdentifierInfo *EnableIfII =
10478 EnableIfDecl->getDeclName().getAsIdentifierInfo();
10479 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
10480 return false;
10481
10482 // Assume the first template argument is the condition.
10483 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
10484
10485 // Dig out the condition.
10486 Cond = nullptr;
10487 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
10488 != TemplateArgument::Expression)
10489 return true;
10490
10491 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
10492
10493 // Ignore Boolean literals; they add no value.
10494 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
10495 Cond = nullptr;
10496
10497 return true;
10498}
10499
10500QualType
10501Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10502 SourceLocation KeywordLoc,
10503 NestedNameSpecifierLoc QualifierLoc,
10504 const IdentifierInfo &II,
10505 SourceLocation IILoc,
10506 TypeSourceInfo **TSI,
10507 bool DeducedTSTContext) {
10508 QualType T = CheckTypenameType(Keyword, KeywordLoc, QualifierLoc, II, IILoc,
10509 DeducedTSTContext);
10510 if (T.isNull())
10511 return QualType();
10512
10513 *TSI = Context.CreateTypeSourceInfo(T);
10514 if (isa<DependentNameType>(T)) {
10515 DependentNameTypeLoc TL =
10516 (*TSI)->getTypeLoc().castAs<DependentNameTypeLoc>();
10517 TL.setElaboratedKeywordLoc(KeywordLoc);
10518 TL.setQualifierLoc(QualifierLoc);
10519 TL.setNameLoc(IILoc);
10520 } else {
10521 ElaboratedTypeLoc TL = (*TSI)->getTypeLoc().castAs<ElaboratedTypeLoc>();
10522 TL.setElaboratedKeywordLoc(KeywordLoc);
10523 TL.setQualifierLoc(QualifierLoc);
10524 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IILoc);
10525 }
10526 return T;
10527}
10528
10529/// Build the type that describes a C++ typename specifier,
10530/// e.g., "typename T::type".
10531QualType
10532Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
10533 SourceLocation KeywordLoc,
10534 NestedNameSpecifierLoc QualifierLoc,
10535 const IdentifierInfo &II,
10536 SourceLocation IILoc, bool DeducedTSTContext) {
10537 CXXScopeSpec SS;
10538 SS.Adopt(QualifierLoc);
10539
10540 DeclContext *Ctx = nullptr;
10541 if (QualifierLoc) {
10542 Ctx = computeDeclContext(SS);
10543 if (!Ctx) {
10544 // If the nested-name-specifier is dependent and couldn't be
10545 // resolved to a type, build a typename type.
10546 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
10547 return Context.getDependentNameType(Keyword,
10548 QualifierLoc.getNestedNameSpecifier(),
10549 &II);
10550 }
10551
10552 // If the nested-name-specifier refers to the current instantiation,
10553 // the "typename" keyword itself is superfluous. In C++03, the
10554 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
10555 // allows such extraneous "typename" keywords, and we retroactively
10556 // apply this DR to C++03 code with only a warning. In any case we continue.
10557
10558 if (RequireCompleteDeclContext(SS, Ctx))
10559 return QualType();
10560 }
10561
10562 DeclarationName Name(&II);
10563 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
10564 if (Ctx)
10565 LookupQualifiedName(Result, Ctx, SS);
10566 else
10567 LookupName(Result, CurScope);
10568 unsigned DiagID = 0;
10569 Decl *Referenced = nullptr;
10570 switch (Result.getResultKind()) {
10571 case LookupResult::NotFound: {
10572 // If we're looking up 'type' within a template named 'enable_if', produce
10573 // a more specific diagnostic.
10574 SourceRange CondRange;
10575 Expr *Cond = nullptr;
10576 if (Ctx && isEnableIf(QualifierLoc, II, CondRange, Cond)) {
10577 // If we have a condition, narrow it down to the specific failed
10578 // condition.
10579 if (Cond) {
10580 Expr *FailedCond;
10581 std::string FailedDescription;
10582 std::tie(FailedCond, FailedDescription) =
10583 findFailedBooleanCondition(Cond);
10584
10585 Diag(FailedCond->getExprLoc(),
10586 diag::err_typename_nested_not_found_requirement)
10587 << FailedDescription
10588 << FailedCond->getSourceRange();
10589 return QualType();
10590 }
10591
10592 Diag(CondRange.getBegin(),
10593 diag::err_typename_nested_not_found_enable_if)
10594 << Ctx << CondRange;
10595 return QualType();
10596 }
10597
10598 DiagID = Ctx ? diag::err_typename_nested_not_found
10599 : diag::err_unknown_typename;
10600 break;
10601 }
10602
10603 case LookupResult::FoundUnresolvedValue: {
10604 // We found a using declaration that is a value. Most likely, the using
10605 // declaration itself is meant to have the 'typename' keyword.
10606 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10607 IILoc);
10608 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10609 << Name << Ctx << FullRange;
10610 if (UnresolvedUsingValueDecl *Using
10611 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10612 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10613 Diag(Loc, diag::note_using_value_decl_missing_typename)
10614 << FixItHint::CreateInsertion(Loc, "typename ");
10615 }
10616 }
10617 // Fall through to create a dependent typename type, from which we can recover
10618 // better.
10619 LLVM_FALLTHROUGH;
10620
10621 case LookupResult::NotFoundInCurrentInstantiation:
10622 // Okay, it's a member of an unknown instantiation.
10623 return Context.getDependentNameType(Keyword,
10624 QualifierLoc.getNestedNameSpecifier(),
10625 &II);
10626
10627 case LookupResult::Found:
10628 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10629 // C++ [class.qual]p2:
10630 // In a lookup in which function names are not ignored and the
10631 // nested-name-specifier nominates a class C, if the name specified
10632 // after the nested-name-specifier, when looked up in C, is the
10633 // injected-class-name of C [...] then the name is instead considered
10634 // to name the constructor of class C.
10635 //
10636 // Unlike in an elaborated-type-specifier, function names are not ignored
10637 // in typename-specifier lookup. However, they are ignored in all the
10638 // contexts where we form a typename type with no keyword (that is, in
10639 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10640 //
10641 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10642 // ignore functions, but that appears to be an oversight.
10643 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10644 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10645 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10646 FoundRD->isInjectedClassName() &&
10647 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10648 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10649 << &II << 1 << 0 /*'typename' keyword used*/;
10650
10651 // We found a type. Build an ElaboratedType, since the
10652 // typename-specifier was just sugar.
10653 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10654 return Context.getElaboratedType(Keyword,
10655 QualifierLoc.getNestedNameSpecifier(),
10656 Context.getTypeDeclType(Type));
10657 }
10658
10659 // C++ [dcl.type.simple]p2:
10660 // A type-specifier of the form
10661 // typename[opt] nested-name-specifier[opt] template-name
10662 // is a placeholder for a deduced class type [...].
10663 if (getLangOpts().CPlusPlus17) {
10664 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10665 if (!DeducedTSTContext) {
10666 QualType T(QualifierLoc
10667 ? QualifierLoc.getNestedNameSpecifier()->getAsType()
10668 : nullptr, 0);
10669 if (!T.isNull())
10670 Diag(IILoc, diag::err_dependent_deduced_tst)
10671 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD)) << T;
10672 else
10673 Diag(IILoc, diag::err_deduced_tst)
10674 << (int)getTemplateNameKindForDiagnostics(TemplateName(TD));
10675 Diag(TD->getLocation(), diag::note_template_decl_here);
10676 return QualType();
10677 }
10678 return Context.getElaboratedType(
10679 Keyword, QualifierLoc.getNestedNameSpecifier(),
10680 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10681 QualType(), false));
10682 }
10683 }
10684
10685 DiagID = Ctx ? diag::err_typename_nested_not_type
10686 : diag::err_typename_not_type;
10687 Referenced = Result.getFoundDecl();
10688 break;
10689
10690 case LookupResult::FoundOverloaded:
10691 DiagID = Ctx ? diag::err_typename_nested_not_type
10692 : diag::err_typename_not_type;
10693 Referenced = *Result.begin();
10694 break;
10695
10696 case LookupResult::Ambiguous:
10697 return QualType();
10698 }
10699
10700 // If we get here, it's because name lookup did not find a
10701 // type. Emit an appropriate diagnostic and return an error.
10702 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10703 IILoc);
10704 if (Ctx)
10705 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10706 else
10707 Diag(IILoc, DiagID) << FullRange << Name;
10708 if (Referenced)
10709 Diag(Referenced->getLocation(),
10710 Ctx ? diag::note_typename_member_refers_here
10711 : diag::note_typename_refers_here)
10712 << Name;
10713 return QualType();
10714}
10715
10716namespace {
10717 // See Sema::RebuildTypeInCurrentInstantiation
10718 class CurrentInstantiationRebuilder
10719 : public TreeTransform<CurrentInstantiationRebuilder> {
10720 SourceLocation Loc;
10721 DeclarationName Entity;
10722
10723 public:
10724 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10725
10726 CurrentInstantiationRebuilder(Sema &SemaRef,
10727 SourceLocation Loc,
10728 DeclarationName Entity)
10729 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10730 Loc(Loc), Entity(Entity) { }
10731
10732 /// Determine whether the given type \p T has already been
10733 /// transformed.
10734 ///
10735 /// For the purposes of type reconstruction, a type has already been
10736 /// transformed if it is NULL or if it is not dependent.
10737 bool AlreadyTransformed(QualType T) {
10738 return T.isNull() || !T->isInstantiationDependentType();
10739 }
10740
10741 /// Returns the location of the entity whose type is being
10742 /// rebuilt.
10743 SourceLocation getBaseLocation() { return Loc; }
10744
10745 /// Returns the name of the entity whose type is being rebuilt.
10746 DeclarationName getBaseEntity() { return Entity; }
10747
10748 /// Sets the "base" location and entity when that
10749 /// information is known based on another transformation.
10750 void setBase(SourceLocation Loc, DeclarationName Entity) {
10751 this->Loc = Loc;
10752 this->Entity = Entity;
10753 }
10754
10755 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10756 // Lambdas never need to be transformed.
10757 return E;
10758 }
10759 };
10760} // end anonymous namespace
10761
10762/// Rebuilds a type within the context of the current instantiation.
10763///
10764/// The type \p T is part of the type of an out-of-line member definition of
10765/// a class template (or class template partial specialization) that was parsed
10766/// and constructed before we entered the scope of the class template (or
10767/// partial specialization thereof). This routine will rebuild that type now
10768/// that we have entered the declarator's scope, which may produce different
10769/// canonical types, e.g.,
10770///
10771/// \code
10772/// template<typename T>
10773/// struct X {
10774/// typedef T* pointer;
10775/// pointer data();
10776/// };
10777///
10778/// template<typename T>
10779/// typename X<T>::pointer X<T>::data() { ... }
10780/// \endcode
10781///
10782/// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10783/// since we do not know that we can look into X<T> when we parsed the type.
10784/// This function will rebuild the type, performing the lookup of "pointer"
10785/// in X<T> and returning an ElaboratedType whose canonical type is the same
10786/// as the canonical type of T*, allowing the return types of the out-of-line
10787/// definition and the declaration to match.
10788TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10789 SourceLocation Loc,
10790 DeclarationName Name) {
10791 if (!T || !T->getType()->isInstantiationDependentType())
10792 return T;
10793
10794 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10795 return Rebuilder.TransformType(T);
10796}
10797
10798ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10799 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10800 DeclarationName());
10801 return Rebuilder.TransformExpr(E);
10802}
10803
10804bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10805 if (SS.isInvalid())
10806 return true;
10807
10808 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10809 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10810 DeclarationName());
10811 NestedNameSpecifierLoc Rebuilt
10812 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10813 if (!Rebuilt)
10814 return true;
10815
10816 SS.Adopt(Rebuilt);
10817 return false;
10818}
10819
10820/// Rebuild the template parameters now that we know we're in a current
10821/// instantiation.
10822bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10823 TemplateParameterList *Params) {
10824 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10825 Decl *Param = Params->getParam(I);
10826
10827 // There is nothing to rebuild in a type parameter.
10828 if (isa<TemplateTypeParmDecl>(Param))
10829 continue;
10830
10831 // Rebuild the template parameter list of a template template parameter.
10832 if (TemplateTemplateParmDecl *TTP
10833 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10834 if (RebuildTemplateParamsInCurrentInstantiation(
10835 TTP->getTemplateParameters()))
10836 return true;
10837
10838 continue;
10839 }
10840
10841 // Rebuild the type of a non-type template parameter.
10842 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10843 TypeSourceInfo *NewTSI
10844 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10845 NTTP->getLocation(),
10846 NTTP->getDeclName());
10847 if (!NewTSI)
10848 return true;
10849
10850 if (NewTSI->getType()->isUndeducedType()) {
10851 // C++17 [temp.dep.expr]p3:
10852 // An id-expression is type-dependent if it contains
10853 // - an identifier associated by name lookup with a non-type
10854 // template-parameter declared with a type that contains a
10855 // placeholder type (7.1.7.4),
10856 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10857 }
10858
10859 if (NewTSI != NTTP->getTypeSourceInfo()) {
10860 NTTP->setTypeSourceInfo(NewTSI);
10861 NTTP->setType(NewTSI->getType());
10862 }
10863 }
10864
10865 return false;
10866}
10867
10868/// Produces a formatted string that describes the binding of
10869/// template parameters to template arguments.
10870std::string
10871Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10872 const TemplateArgumentList &Args) {
10873 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10874}
10875
10876std::string
10877Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10878 const TemplateArgument *Args,
10879 unsigned NumArgs) {
10880 SmallString<128> Str;
10881 llvm::raw_svector_ostream Out(Str);
10882
10883 if (!Params || Params->size() == 0 || NumArgs == 0)
10884 return std::string();
10885
10886 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10887 if (I >= NumArgs)
10888 break;
10889
10890 if (I == 0)
10891 Out << "[with ";
10892 else
10893 Out << ", ";
10894
10895 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10896 Out << Id->getName();
10897 } else {
10898 Out << '$' << I;
10899 }
10900
10901 Out << " = ";
10902 Args[I].print(getPrintingPolicy(), Out);
10903 }
10904
10905 Out << ']';
10906 return std::string(Out.str());
10907}
10908
10909void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10910 CachedTokens &Toks) {
10911 if (!FD)
10912 return;
10913
10914 auto LPT = std::make_unique<LateParsedTemplate>();
10915
10916 // Take tokens to avoid allocations
10917 LPT->Toks.swap(Toks);
10918 LPT->D = FnD;
10919 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10920
10921 FD->setLateTemplateParsed(true);
10922}
10923
10924void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10925 if (!FD)
10926 return;
10927 FD->setLateTemplateParsed(false);
10928}
10929
10930bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10931 DeclContext *DC = CurContext;
10932
10933 while (DC) {
10934 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10935 const FunctionDecl *FD = RD->isLocalClass();
10936 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10937 } else if (DC->isTranslationUnit() || DC->isNamespace())
10938 return false;
10939
10940 DC = DC->getParent();
10941 }
10942 return false;
10943}
10944
10945namespace {
10946/// Walk the path from which a declaration was instantiated, and check
10947/// that every explicit specialization along that path is visible. This enforces
10948/// C++ [temp.expl.spec]/6:
10949///
10950/// If a template, a member template or a member of a class template is
10951/// explicitly specialized then that specialization shall be declared before
10952/// the first use of that specialization that would cause an implicit
10953/// instantiation to take place, in every translation unit in which such a
10954/// use occurs; no diagnostic is required.
10955///
10956/// and also C++ [temp.class.spec]/1:
10957///
10958/// A partial specialization shall be declared before the first use of a
10959/// class template specialization that would make use of the partial
10960/// specialization as the result of an implicit or explicit instantiation
10961/// in every translation unit in which such a use occurs; no diagnostic is
10962/// required.
10963class ExplicitSpecializationVisibilityChecker {
10964 Sema &S;
10965 SourceLocation Loc;
10966 llvm::SmallVector<Module *, 8> Modules;
10967
10968public:
10969 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10970 : S(S), Loc(Loc) {}
10971
10972 void check(NamedDecl *ND) {
10973 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10974 return checkImpl(FD);
10975 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10976 return checkImpl(RD);
10977 if (auto *VD = dyn_cast<VarDecl>(ND))
10978 return checkImpl(VD);
10979 if (auto *ED = dyn_cast<EnumDecl>(ND))
10980 return checkImpl(ED);
10981 }
10982
10983private:
10984 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10985 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10986 : Sema::MissingImportKind::ExplicitSpecialization;
10987 const bool Recover = true;
10988
10989 // If we got a custom set of modules (because only a subset of the
10990 // declarations are interesting), use them, otherwise let
10991 // diagnoseMissingImport intelligently pick some.
10992 if (Modules.empty())
10993 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10994 else
10995 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10996 }
10997
10998 // Check a specific declaration. There are three problematic cases:
10999 //
11000 // 1) The declaration is an explicit specialization of a template
11001 // specialization.
11002 // 2) The declaration is an explicit specialization of a member of an
11003 // templated class.
11004 // 3) The declaration is an instantiation of a template, and that template
11005 // is an explicit specialization of a member of a templated class.
11006 //
11007 // We don't need to go any deeper than that, as the instantiation of the
11008 // surrounding class / etc is not triggered by whatever triggered this
11009 // instantiation, and thus should be checked elsewhere.
11010 template<typename SpecDecl>
11011 void checkImpl(SpecDecl *Spec) {
11012 bool IsHiddenExplicitSpecialization = false;
11013 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
11014 IsHiddenExplicitSpecialization =
11015 Spec->getMemberSpecializationInfo()
11016 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
11017 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
11018 } else {
11019 checkInstantiated(Spec);
11020 }
11021
11022 if (IsHiddenExplicitSpecialization)
11023 diagnose(Spec->getMostRecentDecl(), false);
11024 }
11025
11026 void checkInstantiated(FunctionDecl *FD) {
11027 if (auto *TD = FD->getPrimaryTemplate())
11028 checkTemplate(TD);
11029 }
11030
11031 void checkInstantiated(CXXRecordDecl *RD) {
11032 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
11033 if (!SD)
11034 return;
11035
11036 auto From = SD->getSpecializedTemplateOrPartial();
11037 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
11038 checkTemplate(TD);
11039 else if (auto *TD =
11040 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
11041 if (!S.hasVisibleDeclaration(TD))
11042 diagnose(TD, true);
11043 checkTemplate(TD);
11044 }
11045 }
11046
11047 void checkInstantiated(VarDecl *RD) {
11048 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
11049 if (!SD)
11050 return;
11051
11052 auto From = SD->getSpecializedTemplateOrPartial();
11053 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
11054 checkTemplate(TD);
11055 else if (auto *TD =
11056 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
11057 if (!S.hasVisibleDeclaration(TD))
11058 diagnose(TD, true);
11059 checkTemplate(TD);
11060 }
11061 }
11062
11063 void checkInstantiated(EnumDecl *FD) {}
11064
11065 template<typename TemplDecl>
11066 void checkTemplate(TemplDecl *TD) {
11067 if (TD->isMemberSpecialization()) {
11068 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
11069 diagnose(TD->getMostRecentDecl(), false);
11070 }
11071 }
11072};
11073} // end anonymous namespace
11074
11075void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
11076 if (!getLangOpts().Modules)
11077 return;
11078
11079 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
11080}
11081